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The SPS Weblog
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Take the MIT Weblog Survey
This is a general social survey of the greater weblog community being conducted at
the Massachusetts Institute of Technology.Some additional early%20resultsfrom%20the%20survey%20look%20interesting. %20The%20full%20results%20should%20be%20coming%20out%20soon,%20so%20if%20you%20haven’t%20taken%20the%20survey,%20but%20want%20to,%20now’s%20the%20time.
They’ve%20provided%20some%20more%20
information about the survey, privacy etc..Ran into this survey while reading Rockford
Lhotka’s Weblog.
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Visual Basic to Visual FoxPro Conversion Utility
Visual Basic (versions 6 and below) code examples are everywhere. It’s a huge
resource that many Visual FoxPro developers utilize, but converting a Visual Basic
example to Visual FoxPro is, more often than not, a pain. It’s the same thing over
and over again… change dims to locals, change msgbox to messagebox, add parenthesis
around the procedure calls, etc., etc., ad nauseam.As a programmer who develops in Visual Basic as well as Visual FoxPro, I was
intrigued when, about a year ago on Tek-Tips, William GC Steinford offered the
idea of a Visual Basic to Visual FoxPro converter. I decided it was a great idea and
created my own. It is driven from a conversion table (of course), and handles most
of the basic things that need to be changed when porting Visual Basic code to Visual
FoxPro.I’ve used it internally for awhile now, and it is a real time saver. Now, bear
in mind that I’m not putting on a code clinic with this thing (like I said, I was
just using it internally for some down and dirty conversions), but it’s functional
and new vb to vfp syntax conversions can be added to the program just by adding records
in the conversion.dbf. There are a couple of extra fields in that table as well
that are reserved for future use (they will be used for such things as converting
API Declare statements properly and such – basically anything that can’t be done in
one pass through the conversion.dbf or needs special handling).If you add to the conversion table or the program, I would really appreciate
it if you would email me the changes. I would like to incorporate any useful
changes with my own, and continue to offer them back to the Visual FoxPro community.
Other than that, feel free to use it however or whenever you see fit.A sample Visual Basic .BAS file has been included in the zip. When you run the vbtovfp.exe
just click the ellipsis button […] and select the vbsample.bas file to open it in
the conversion utility. Here’s a screen shot of vbtovfp and you can download vbtovfp
here (source included).Note: Originally written in VFP 7, but ported to VFP 9 – so, you will need VFP 9 to
run this (or take the time to take out the VFP 9-only features and recompile it in
whatever VFP you got). Also, there is selection/right-click functionality with the
editboxes you’ll want to explore.
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Spelling Checker and VFP
Checking the spelling in a given string, such as the text in a control, is something
that a lot of Visual FoxPro applications can use. There are many ways to accomplish
this. Some Visual FoxPro developers use Microsoft Word similar to the way I
did in my FAQ about it. Others
shell out between $250-500 in order to purchase a third-party tool or control that
will get the job done. And some, just do without.Making a Contribution
Well, a couple days ago I was looking for a way to put my
recent blog about the Visual FoxPro Community into action at this end, and I decided
to try my hand at creating a class with the ability to easily add spelling checks
to Visual FoxPro applications. Here are some of the important steps I took, followed
by a screen capture of spelling checker I created in Visual FoxPro and a
couple of links, so you can download a copy of the project (all source code included),
some runnable examples, and even an alternate dictionary table.Step 1:
Find a way to recognize a misspelling. Obviously I needed a dictionary. Luckily
there are plenty of open source dictionaries out there, and I soon I had compiled
a dictionary table of 144,238 words. The words came from Kevin
Atkinson’s Spell Checking Oriented Word Lists (SCOWL). I took English and American
words up to level 70. Level 80 and 95 words are mostly obscure (scrabble players only),
removed possessive words and duplicates, and gave it a few final tweaks. 140,000+
words is a nice size dictionary for any spelling checker.Step 2:
Give the user some choices of possible matches. Here again I was lucky in
that I’ve worked on a number of sounds-like algorithms for Visual FoxPro in the past
(including: Improved Soundex, Metaphone,
and Double
Metaphone). In this case, because I was dealing with English words the Improved
Soundex was all that was needed, and it is the fastest of the alternatives so that
was a Win-Win. However, this only handled misspellings that sound like the actual
spelling, if I ran into “thwrw” because the user’s finger had slipped
to the “w” instead of the “e”, the Improved Soundex algorithm
wasn’t going to do me much good.Well, it just so happened that I had run into a posting of a class method for
computing the Levenshtein
Distance in Visual FoxPro and I had rewritten it (see the bottom of the page I
linked). The Levenshtein
Distance is an excellent indicator of how closely matched two words are even though
they don’t sound the same.Step 3:
With the first two hurdles overcome, it was time to figure out what kind
of design I would go for. I decided on doing the entire thing with classes and in
such a way that new user interfaces could be created and hooked up. Now, bear in mind
that this is just my first stab at it and less than two days have gone by, but I think
you’ll see some things you like if you care enough to dig into it.Before I go any further let me say that I have not put the error handling into it
yet. That will go in next. I find with projects of this size (and when there is a
high potential for me to be changing my mind while coding) that it is easiest to put
the error handling in once the design has stabilized. So please, no flames about the
lack of any error handling… it’s on the way. Or, better yet, since it will be a
couple of days before I can get back to this, how about you throw in some really nice
Try…Catch…Finally commands in it and shoot it back to me? LOL.The guts of the spelling checker is in the spellcheck class in spellcheck.vcx and
my first stab at an interface is the splchkdialog class in spellcheck.vcx. Other
than that the class library just holds a bunch of subclasses of the Visual FoxPro
base classes. I want to encapsulate the logic even further, so interfaces are a complete
snap to create and the spellcheck class is a black box engine (but it’s still pretty
decent as it sits now).Step 4:
Return a list of suggestions for the user to pick from as replacements for a given
misspelling really fast. I had to figure out a way to tweak the returned suggestion
list that would handle the size of the dictionary table. I decided on an SQL
select statement because of its flexibility and speed when optimized. Then I defined
the criteria for the SQL where clause. I also ordered the elements in the Where
clause so that the criteria that would weed out the most entries came first and the
most resource intensive operations (such as the Levenshtein Distance) would come last.This still wasn’t fast enough, so I created another field in the dictionary table
to hold the Improved Soundex codes for the words and indexed it. And created an index
on the LEN(ALLTRIM()) of the word as well. This dramatically improved the speed and
after a few more tweaks I had a workable SQL for returning the results. See the getsuggestions
method of the spellcheck class.Step 5:
Logically order the results returned to the user. Alphabetical returns are anything
but logical when returning suggestions for a spellchecker. I decided to add a weight
field to the suggestions curosr and base it on different aspects of the
matches between the word in question and the words in the dictionary table. In
this case, I went with lower weights meaning better the matches. The weight made
an excellent field to base the Order by clause on as well. The top 10 results
were finally being returned in a logical order. To see the way the weight is figured,
look in the figureweight method of the spellcheck class.Step 6:
Test, tweak, test fix… drink more coffee and Red Bull energy drink… Test,
tweak, test, fix. And finally, create two examples, write a README.txt, zip it all
up, take a couple screen shots, and write this blog. The download link is provided
below (look on the right-hand side), full source included, don’t forget to read the
README.txt.Visual FoxPro Spelling Checker
Download VFP Spelling Checker (2MB
approx.)UPDATES: 07-31-2005 Created a new dictionary table based on the SCOWL so that copyright
and redistribution rights were sure (removed previous two dictionaries). Optimized
some code, fixed a couple of bugs, worked in the new dictionary and edited this blog
entry to apply to the new dictionary table.
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Skinning a Form in Visual FoxPro
Sometime ago I incorporated VFPSkin elements
into a project I was working on. This was when VFPSkin had first come out (version
1.0?) and was still free and open source. I was pretty impressed with VFPSkin
as I had never seen skinning for Visual FoxPro applications prior to this. It was
a little buggy and I made a lot of modifications, but overall the idea was sound and
ingenious. (Just for the record, I made it a point not to look at VFPSkin’s source
code while I created the example for this blog entry. I admit having been exposed
to VFPSkin and thus influenced by it, but the code and parts of this example
were created from scratch.)So, that was extent of my exposure to skins in Visual FoxPro… fast forward
to today. I decided to take a look at creating a simplified way to skin Visual FoxPro
screens. Why? Well, as with most of my ideas and side projects, sometimes it’s the
challenge and other times I just have an idea for something that might be helpful
to the Visual FoxPro Community and I want to explore it a little. In this case,
as in most, it was a little of both. I call this project “Green Screen”.The idea was to take a single ordinary bitmap that has a unique background
color (transparency key if you will), use it for the picture property of a form, and
then carve out everything at runtime based on that unique color. In this case I chose
green for the color — just like in the movies (that’s where I got the idea,
though these days I think Hollywood uses mostly blue) — and I created a simple sample
skin that I could use during development.
Green Screen Skin BmpUsing some API calls (CreateRectRgn and CombineRgn in
GDI32 and SetWindowRgn in USER32) the project quickly progressed and I soon had
a form that displayed just the intended portion of the bitmap skin. Next it was time
to create a routine that would allow Visual FoxPro developers to use their own bitmaps
and create “skin definition files” based on them. I decided to incorporate this portion
into my example form as well.This is just a quick initial stab at it… consider
it a pretty decent proof of concept. My ultimate goal for this portion was to show
Visual FoxPro developers how skinning can be accomplished in a simple, straightforward
way. It took much less than a day to get this far, so imagine what can be done given
time. Next up on my todo list will be the ability to resize the form (as well as maximize
and minimize) and also the ability to skin/unskin on demand as well as the ability
to change skins on the fly. I will be keeping an eye towards simplicity throughout,
as I want this to be a very painless tool for Visual FoxPro developers to use.A couple of quick final notes: The two methods in
the example form that you’ll want to take a look at are createskindefinition and readskindefinition.
Though I chose green as the unique color, it can be anything. The readskindefinition
method will look at a single pixel in the bottom left of your bitmap to determine
the color that should be carved out of the form. All in all, I think you might be
surprised at minimal amount of code it took to actually pull this off. Here’s a screen
shot of the example and the customary download link.Download
Green Screen Example (10 KB approx.)
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Splitter Class for Visual FoxPro
A number of other languages have a splitter control of some sort, why not Visual FoxPro?
To be fair, I have seen some splitter classes floating around from time to time, but
I thought I’d try my hand at it. I was convinced it couldn’t be too difficult, and
Visual FoxPro didn’t disappoint me. Below is a download link for the class library
that I placed my splitter class in (based on shape) and an example form showing how
the class is used (I’ve taken a screen shot of it so you can see what it looks
like). Now, if you want to try the splitter class out before you go to the trouble
of downloading it, I’ve also created a cut-n-paste/execute example that you’ll find
directly beneath the screen shot. This splitter control is designed to work with Visual
FoxPro 9.0. If you are using a previous version then you will need to modify/delete
a few things.Download Splitter.vcx
and Form Example (8 KB approx.)
*!* Cut-N-Paste the code below into a prg file and execute it to see and try out a
working example of the splitter classPUBLIC oform1
oform1=NEWOBJECT(“form1”)
oform1.Show
RETURN************************************
DEFINE CLASS form1 AS form
************************************DoCreate = .T.
Caption = “Splitter Example”
Name = “Form1”
MDIForm = .T.
Autocenter = .T.
ADD OBJECT text1 AS textbox WITH ;
Anchor = 11, ;
Height = 29, ;
Left = 0, ;
Top = 0, ;
Width = 375, ;
Name = “Text1”ADD OBJECT edit1 AS editbox WITH ;
Anchor = 7, ;
Height = 217, ;
Left = 0, ;
Top = 33, ;
Width = 184, ;
Name = “Edit1”ADD OBJECT edit2 AS editbox WITH ;
Anchor = 15, ;
Height = 217, ;
Left = 188, ;
Top = 33, ;
Width = 187, ;
Name = “Edit2”ADD OBJECT splitter1 AS splitter WITH ;
Top = 32, ;
Left = 183, ;
Height = 219, ;
Width = 6, ;
Anchor = 7, ;
Name = “Splitter1”ADD OBJECT splitter2 AS splitter WITH ;
Top = 28, ;
Left = 0, ;
Height = 6, ;
Width = 376, ;
Anchor = 10, ;
vertical = .F., ;
minimumsize = 29, ;
Name = “Splitter2”PROCEDURE Init
This.text1.Value = “Visual FoxPro Rocks!”
This.Edit1.Value = “Visual FoxPro is an extremely versatile development
tool. ” + ;
“Not only does it allow a developer to create great datacentric
applications, ” + ;
“it also allows the developer to extend the actual language
with new classes, ” + ;
“code libraries, and hooks. If you’re an avid Visual FoxPro
developer like myself ” + ;
“then good for you. And, if you’re not, then I encourage you
to give Visual FoxPro ” + ;
“a try. You won’t regret it”
This.Edit2.Value = “This is an example of a splitter class for use in
Visual FoxPro 9.0 forms. ” + ;
“It is pure Visual FoxPro, so there aren’t any additional
ActiveX or DLL dependencies ” + ;
“to worry about when distributing your application. To see
it in action move the ” + ;
“horizontal and vertical splitters around on this form. Also,
by resizing the form you ” + ;
“can see that it handles the new Visual FoxPro 9.0 Anchors
property with aplomb.”
ENDPROCENDDEFINE
************************************
DEFINE CLASS splitter AS shape
************************************
Height = 182
Width = 8
MousePointer = 9
SpecialEffect = 0
Style = 0
mousedownat = 0 && Tracks mouse and allows class to ignore moves caused
by resizing form
vertical = .T. && Set to .F. for horizontal splitter
minimumsize = 40 && This is how small (in pixels) the panels can get
when moving the splitter
Name = “splitter”PROCEDURE MouseLeave
LPARAMETERS nButton, nShift, nXCoord, nYCoord
This.mousedownat = 0
ENDPROCPROCEDURE Move
LPARAMETERS nLeft, nTop, nWidth, nHeight
*!* If you want to move the splitter during runtime and have it move the
other controls
*!* then set mousedownat != 0 and call this move method of the splitter
*!* remember to set mousedownat back to 0 when you are done moving the
splitterLOCAL loControl, llLockScreenWas, lnMovement, llIsSplitter, lcUniqueTag,
lnMarginOfError, lnAnchorWas
IF this.MouseDownAt == 0
DODEFAULT(m.nLeft, m.nTop, m.nWidth, m.nHeight)
RETURN
ENDIFm.loControl = NULL
*!* The following tag can be placed in controls you don’t want moved as
well
m.lcUniqueTag = “DoN’t_MoVe_SpLiT” && Just something that is pretty
well guaranteed to be unique
THIS.TAG = m.lcUniqueTag
m.llLockScreenWas = THISFORM.LOCKSCREEN && JIC the screen was
already locked
THISFORM.LOCKSCREEN = .T.m.lnMovementLeft = m.nLeft – THIS.LEFT
m.lnMovementTop = m.nTop – THIS.TopFOR EACH m.loControl IN THIS.PARENT.CONTROLS
IF m.loControl.TAG = lcUniqueTag && this splitter so just
loop
LOOP
ENDIF
IF PEMSTATUS(m.loControl,”Anchor”,5)
m.lnAnchorWas = m.loControl.Anchor
m.loControl.Anchor = 0
m.llIsSplitter = m.loControl.CLASS = “Splitter”
IF THIS.vertical && Vertical Splitter
lnMarginOfError = INT(This.width/2) && JIC the
developer got the splitter a little too close
IF m.loControl.LEFT <= THIS.LEFT && Control
is to the left of splitter
IF (m.loControl.LEFT + m.loControl.WIDTH) <=
(THIS.LEFT + lnMarginOfError) AND !m.llIsSplitter
m.loControl.WIDTH = MAX(m.loControl.WIDTH
+ m.lnMovementLeft, 0)
ENDIF
ELSE && Control is to the right of splitter
IF !m.llIsSplitter
m.loControl.WIDTH = MAX(m.loControl.WIDTH
– m.lnMovementLeft, 0)
ENDIF
m.loControl.LEFT = m.loControl.LEFT + m.lnMovementLeft
ENDIF
ELSE && Horizontal Splitter
lnMarginOfError = INT(This.Top/2) && JIC the
developer got the splitter a little too close
IF m.loControl.TOP <= THIS.TOP && Control
is above the splitter
IF (m.loControl.TOP + m.loControl.HEIGHT) <=
(THIS.TOP + lnMarginOfError) AND !m.llIsSplitter
m.loControl.HEIGHT = MAX(m.loControl.HEIGHT
+ m.lnMovementTop, 0)
ENDIF
ELSE && Control is below the splitter
IF !m.llIsSplitter
m.loControl.HEIGHT = MAX(m.loControl.HEIGHT
– m.lnMovementTop, 0)
ENDIF
m.loControl.TOP = m.loControl.TOP + m.lnMovementTop
ENDIF
ENDIF
m.loControl.Anchor = m.lnAnchorWas
ENDIF
NEXT
m.lnAnchorWas = This.Anchor
This.Anchor = 0
DODEFAULT(m.nLeft, m.nTop, m.nWidth, m.nHeight) && Finally move
the splitter
This.Anchor = m.lnAnchorWas
THISFORM.LOCKSCREEN = m.llLockScreenWas
THIS.TAG = “”
ENDPROCPROCEDURE MouseMove
LPARAMETERS nButton, nShift, nXCoord, nYCoord
LOCAL lnMovement
IF m.nButton = 1 AND !(this.mousedownat == 0)
IF THIS.vertical
IF m.nXCoord != THIS.mousedownat
m.lnMovement = m.nXCoord – THIS.mousedownat
IF BETWEEN(THIS.LEFT + m.lnMovement, This.minimumsize,
THIS.PARENT.WIDTH – THIS.WIDTH – This.minimumsize)
THIS.MOVE(THIS.LEFT + m.lnMovement, THIS.TOP,
THIS.WIDTH, THIS.HEIGHT)
THIS.mousedownat = m.nXCoord
ENDIF
ENDIF
ELSE && Horizontal
IF m.nYCoord != THIS.mousedownat
m.lnMovement = m.nYCoord – THIS.mousedownat
IF BETWEEN(THIS.TOP + m.lnMovement, This.minimumsize,
THIS.PARENT.HEIGHT – THIS.HEIGHT – This.minimumsize)
THIS.MOVE(THIS.LEFT, THIS.TOP + m.lnMovement,
THIS.WIDTH, THIS.HEIGHT)
THIS.mousedownat = m.nYCoord
ENDIF
ENDIF
ENDIF
ENDIF
ENDPROCPROCEDURE MouseDown
LPARAMETERS nButton, nShift, nXCoord, nYCoord
IF THIS.vertical
THIS.mousedownat = nXCoord
ELSE
THIS.mousedownat = nYCoord
ENDIF
ENDPROCPROCEDURE Init
IF !THIS.vertical
THIS.MOUSEPOINTER = 7 && NS
ENDIF
ENDPROCPROCEDURE MouseUp
LPARAMETERS nButton, nShift, nXCoord, nYCoord
This.mousedownat = 0
ENDPROC
ENDDEFINE
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New ReportPreview App for Visual FoxPro
The ReportPreview.app is a pretty good general preview application
for Visual FoxPro 9. The look of it mimics the report preview screen we had prior
to Visual FoxPro 9 and it provides much of the same functionality as well as some
new features available in Visual FoxPro 9 thrown in for good measure. However, some
Visual FoxPro developers are having problems with certain aspects of it.Running ReportPreview.app as a modal preview (report form command) in
a TopLevel form application will cause the print preview toolbar to stop responding.
That’s because the ReportPreview.app brings the preview form up in a modal state and
toolbars are not accessible when a modal form is active. For the most part, this is
as it should be and is in-line with Microsoft Windows conventions. The answer is to
include the NOWAIT clause in the report form command or you can modify the ReportPreview.pjx
to force it into a modeless state when this situation occurs. Easy enough right? Well,
the problem with this approach is it usually defeats the very thing that the developer
is attempting to do… mainly, bring up a modal preview window in a TopLevel application
(I want the preview window to come up, then I want to wait until the user has released
the preview window before continuing with my code execution).If you haven’t run into the aforementioned problem you can reproduce
it by opening up the Taskpane in Visual FoxPro and go to the Solutions Samples
area. Then expand the “New in Visual FoxPro 9.0” node and look for the “The typical
multiple detail band report” sample. Over on the right-hand side of the sample there
is a little report and magnifying glass button that says “Click here to view the code”
in its tooltip, click that button. Next modify the ShowWindow property of the
form that pops up (ShowWindow = 2 – As Top-Level Form). Close the form and save your
changes, then run the sample. You’ll notice that the toolbar does not respond to user
events. To close the sample you’ll have to close the report from the “X” in the top
right corner of the preview window.Another thing about the ReportPreview.app is that it looks a little
antiquated to me. I may be the only one that feels this way, but I suspect not. Now,
before the flames start… I’m not saying that I don’t think the MS Fox Team didn’t
do a good job. I’m all for having them just give us access and allow us, as seasoned
Visual FoxPro developers, develop the rest. I don’t want them wasting time mocking
up Visual FoxPro forms and applications that I can create myself. I feel like we are
all well served by them opening the guts of Visual FoxPro up to us as developers,
give a basic example of the new feature’s use, and then let us do the rest.So, last night I decided to rip into the ReportPreview.pjx and see
what I could do. I made an exact copy of the entire Report Preview project folder
from XSource and then began modifying it. Basically keeping the stuff I liked, deleting
the stuff I didn’t, and modifying the rest. The result was a ReportPreviewEx.app that
can be used in lieu of the ReportPreview.app. To use it you’ll need to set the _reportpreview
system variable to the new application:_reportpreview
= “reportpreviewex.app”>
This will cause Visual FoxPro to use the new print
preview application. To try it out run one of the report samples in the Solutions
Samples area of the Taskpane underneath the “New in Visual FoxPro 9.0” node. The names
of the samples are “A multiple detail band report used for calculations” and “The
typical multiple detail band report”.This new application doesn’t suffer from some of the
drawbacks the ReportPreview.app does. For instance, instead of toolbar, I placed the
buttons and such directly on the frxpreviewform class. This fixes the problem with
modal previews in a TopLevel application and is more in-line with print preview windows
such as the one in Internet Explorer.I ran into more than a few issues while creating
this, but almost all of them have been resolved successfully. However, one issue that
is still plaguing me is the way the MS Fox Team failed to implement double-buffering
correctly when rendering emf content in an image control. Emf file format is perfect
for reports because meta-files scale better than anything else on the planet. But,
when you are running the print preview you are going to see a slight flicker. Regrettably
the MS Fox Team has not opened up the internal painting routines to us, so I am unable
to insert the proper code that should be used when Visual FoxPro is repainting the
image controls. That having been said, I added a property to the frxpreviewform form
class of the frxpreview.vcx that allows you to try out all the other formats and their
results. The property is “outputimagetype” and has the following possible values:
tiff, bmp, png, jpeg, gif, emf. If you want to try another format that doesn’t have
the flicker and still has perhaps acceptable quality, change the property to “png”.
The drawback to this format is that it looks blurry at large zoom levels and Visual
FoxPro turns into a bit of a performance hog with its internal painting routines.I posted a comment on Calvin
Hsia’s blog recently asking him to pull the curtain back further on the internal
painting routines for Visual FoxPro, and I’ve asked other members of the Fox Team
in the past to please give us a little insight into this so we can address issues
such as this effectively and help Microsoft out a little at the same time. Regrettably,
they have ignored me so far. I wish that their new goal of transparency extended towards
the Visual FoxPro core as well. I understand that they have trade secrets/intellectual
property rights to consider, but I think they could use some help in this particular
area.Now some of you are no doubt thinking, why didn’t Craig
just use the outputpage method of the Report Listener class to render to a canvas
object (shape or container control). The reason is that Visual FoxPro will paint right
over the top of anything that gets in the way of the canvas object. So, if you have
a bunch of canvas objects inside a container and you are allowing the canvas objects
to be slid around inside the container so that portions of them are outside the dimensions
of the visible container (left = -150 or top = -200 or whatever), the Report Listener
doesn’t respect the container’s borders, so it starts rendering the report right over
the top of other form elements. So, the answer is to use an image control and temporary
off-screen bitmaps assigned to their picture property. Why not a container (it has
a picture property)? Well with the image control I pick up a little more overhead,
but it gives me some really good additional functionality for free (such as the stretch
property that makes zooming in and out on print preview a breeze from a coding standpoint).
There’s more to this whole sorted saga, but I think you get the general idea.So, here’s a screen capture of the new print preveiw,
a link to download the ReportPreviewEx.app, and an additional link to download
the entire source — IMPORTANT NOTE: I’ve just looked through
the redist.txt that comes with Visual FoxPro and I cannot find anywhere that certain
elements of the ReportPreview.pjx are on the allowable list – I will email Microsoft
for clarification – until I hear back from them, I have removed the source code link.Download
ReportPreviewEx Application (approx. 47 KB)
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Rubberband Selections in Visual FoxPro
The day before yesterday I was surfing my blogroll and came across an interesting
post by Calvin Hsia — “Enable
crop and zooming in on your digital photograph display form“. It was using GDI+
in a Visual FoxPro form and, since I am writing a series of articles for FoxTalk on
the subject, it caught my eye. One of the things I liked the most about Calvin’s entry
was the idea of using a shape in order to create a rubberband selection area; basically a
rectangle with a dotted line border that you may have noticed once or twice in
various Windows applications (still don’t know what I’m talking about? Go to your
desktop and left click and drag a rubberband selection area around some icons — or
just look at the screen shot below). I came away from Calvin’s entry thinking he had
a great idea, so I’ve implemented my own and expanded on it.I created a class called “rubberband” that can be added through code to any form
during runtime. It facilitates a rubberband selector when the user drags their mouse
over the surface of the form. This class has several features that I thought would
be useful to a developer.-
The rubberband is reversible, meaning it can follow the mouse no matter which way
the user maybe dragging their selection area. -
It provides feedback when the selection is started, when the selection area is
changed, and also when the selection has been completed. -
It has an optional feature that will allow you to get a collection of the selected
objects as well as a collection of objects that aren’t selected based on the selection
area. This is turned on or off via a property of the class named “selectobjects” -
Left or right mouse button can be specified as the active mouse button that creates
the rubberband selection areas. -
Optional keys (shift, alt, or ctrl) can also be specified as required during the selection
(such as, the user must hold the alt key down while dragging with the left mouse button
depressed).
The class makes liberal use of Visual FoxPro’s Bindevent function to monitor the user’s
activity on the form’s surface. And, the example form I’m including in the download
uses bindevents as well to receive feedback from the rubberband class. All-in-all,
it turned out to be a pretty workable solution and implementation of Calvin Hsia’s
idea.One of the problems I ran into however, was when the mouse was over a particular object
on the form, the form obviously didn’t receive the mouse events… so the rubberband
just stops. The solution for this example was to send the mouse events up the chain
to the parent form. However, in perhaps a future blog entry I will use the vfpex.fll
with its BindEventEx/UnBindEventEx functions (if interested you can read my earlier
blog post regarding vfpex.fll) in order to create a mouse hook and keyboard hook in
order to facilitate this without having to send mouseevents up to the parent
object. I’m not sure if BindEventEx would be needed or not, perhaps Visual FoxPro
9.0’s BindEvent would be enough… never hit something with a sledgehammer when a
simple tap will do.Before I go, I just want to say that I highly recommend Calvin
Hsia’s WebLog, there’s a lot of great content there… especially in the archives.
Who knows, if enough people take an interest in his blog, he might give us more secrets.
🙂 Now, without any further ado here’s the usual screen shot and download link. (oh,
and by the way, that weird thing with the fonts getting bolder as the form repaints
definitely needs to be fixed in Visual FoxPro 9.0 — I’ve left it in this example
to maybe draw some more attention to it, see the checkboxes as you play with the example).Download Rubberband
Selector Class and Example Form (9 KB approx.)
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The rubberband is reversible, meaning it can follow the mouse no matter which way
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Visual FoxPro Grid – A Tip and a Calendar Class
Visual FoxPro’s Grid
It is my opinion that the Visual FoxPro grid has gotten a bum rap at times.
Though it does possess it’s share of eccentricities, it is probably one of the most
powerful and useful controls I have ever had the pleasure of working with. The things
that it is capable of doing are simply amazing. Heck, you can have multiple controls
in a column or even put a grid inside a grid, so you essentially have a row/column
intersect (cell) representing many records.In this entry, I want to show you a little known feature of the grid control. If you
know about this feature, then you are one of a handful. When the grid is refreshing or
otherwise repainting it will access the backstyle for every control the columns
contain, and anything you do in there will stick for the individual controls shown
in the grid.Some help from the MS Fox Team
Allow me to try and clarify… let’s say you have a grid with a single column
and that column contains Textbox1. If you set the backcolor of the Textbox1 through
code to, let’s say, the color Red, then every cell shown in column1 will turn red.
So, how to get dynamic colors (individual cells colored differently within the same
column)? Well, the MS Fox Team provides us with some dynamic properties of the column
object that will act on individual cells (DynamicAlignment, DynamicBackColor,
DynamicCurrentControl, DynamicFontBold, DynamicFontItalic, DynamicFontName, DynamicFontOutline,
DynamicFontShadow, DynamicFontSize, DynamicFontStrikeThru, DynamicFontUnderline, DynamicForeColor,
and DynamicInputMask). These are all very useful, and in the scenario I provided the
DynamicBackColor will work nicely to change the backcolor of individual cells within
a column of the grid. But what if you wanted to do something more complex? What if
you had a container in the column and that container contained multiple objects and
you wanted to set their forecolors and backcolors to completely different colors dynamically
or what if you wanted to display different pictures within the grid cells?Developers’ usual and ingenious solutions
One approach to these problems is to use multiple controls within the
column of the grid and then use DynamicCurrentControl to decide which to display.
Such as one textbox that has a red background and another that has a white background,
or different image controls all set to different pictures.Another ingenious method some Visual FoxPro developers imploy when solving this problem
is to subclass the column object and then “hook” into a non-used dynamic property
of the column to use it for other purposes (Such as DynamicForeColor) If the ForeColor
is being set to 1 then do this, if the forecolor is being set to 2 do something else,
if the forecolor is 3… and so on. While this approach and the preceding one are
both valid way of doing this, there is another way.Another way
As previously noted, the backstyle is accessed for the currentcontrol in
a column, and it’s not accessed just once, it is accessed for every visible cell
in the grid. So, using this we can do nearly whatever we want as far as dynamic formatting
and display. Want different images displayed? Just subclass a container and put an
image control within it and place it in the column. Then, in the backstyle_access
method (you’ll need to add this access method to the subclassed container) set the
value of the contained image’s picture property to a field in the recordsource
that holds all the different paths in the image’s backstyle_access method.this.picture = crsImages.Paths
There’s an example of doing this included in the download. When you run the example
it will ask you for a directory containing images. If one is not readily available
to you, you can select the folder the project is in because I have included
the below screen shots in it. This solution is more efficient than having an
image control in the column for each image you want displayed in the grid… 100 images
= 100 image controls? I’d rather just deal with one.Calendar class and real world example
OK, but what about something a little more real world? What kinds of things
is being able to dynamically alter items within a container using the backstyle_access good
for? All sorts of stuff. In order to demonstrate the just one useful example
of this, I put together some quick calendar demos. I’ve created an advanced calendar
class using the grid control. This should demonstrate well the power of utilizing
backstyle_access in a grid, not to mention the power of Visual FoxPro. Below is
the download link for the project source and some screen shots (so you can know what
to expect). There is an executable provided in the source folder for running the examples,
or if you prefer you can run the forms individually. The examples were created using
Visual FoxPro 9.0, so if you’re using an earlier version you will have to modify the
code or better yet, upgrade! There are more great things to come, Visual FoxPro Rocks!Download VFP Calendar
Examples and Source
Just a simple calendar
Demonstrates some of the advanced display features of the calendar
class
Improved Date and DateTime controls created using the calendar
class
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Visual FoxPro Progress Bar Class
Progress bars everywhere you look
I’ve created Visual FoxPro progress bars before (who among us hasn’t right?).
The last time I developed one, I posted it over in the download section of Universal
Thread. It is a COM server progress bar that allows progress indication to
smoothly continue even when Visual FoxPro is busy churning away on a single line of
code. But in today’s project, I set out to create a simpler progress bar that could
be placed in a container (form or whatever).
Another progress bar class
I wanted this progress bar to look really professional. I also wanted it to handle
being resized to any length or width by the developer during design. I then wanted
it to either do a solid bar or create individual blocks like we see in the standard Windows
XP progress bar and I wanted it to have the ability to show the percentage complete
with a label that would change color as the progress bar went over the top of it (so
at 50%, half of the 50% is one color and the other half another). Finally it had to
be able to display different colors (green as in Windows XP, as well as red and
blue). These are all features I’ve seen in other progress bars, and felt that Visual
FoxPro could use one too.
Progressbar properties of note
barcolor = The color you want the progress
bar to be: 1 = Red, 2 = Green, 3 = Blue (defaults to 2)
min = The value to be considered 0% (defaults
to 0)
max = The value to be considered 100%
(defaults to 100)
percentage = The percentage complete based
on the current value assigned (defaults to 0)
showpercentage = Whether the percentage
should be displayed to the user (defaults to .F.; best used when solidbar is .T.)
solidbar = Whether progress bar should
be shown as a solid as opposed to blocks (defaults to .F.)
value = The current value of the progress
(defaults to 0; should fall within the min and max range)Other development notes
The gradient look of the progress bar was created by dynamically adding lines
of varying degrees of color. The percentage showing through the progress bar was facilitated
by setting the drawmode property of the lines to 14 – Merge Pen Not.Download the project
You can either run the progressbarex.exe or you can open the project and
run the example.scx. Everything is included in the download. Here is the download
link and a screen shot of the included example…Download ProgressbarEx
Example and Source (26 KB approx.)
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Visual FoxPro Scrollbar Classes
New Found Respect for Scrollbar Creation
Earlier this evening I decided to create a scrollbar class for use with Visual
FoxPro. My requirements were that it was created purely with Visual FoxPro (didn’t
have any ActiveX dependecies) and that it was professional enough for use in
a real world Visual FoxPro application. It is now five hours later… the
class is complete and I have a new found respect for anyone who successfully creates
scrollbars. This turned out to be one of the more difficult challenges I have given
myself.New VFPScrollBar Class Library
I created my scrollbar classes in a class library called vfpscrollbar.vcx.
The three classes that are of note are the scrollbarhorizontal, scrollbarvertical,
and the sbscrollablecontainer. The sbscrollablecontainer is an example of the types
of classes that can be built using the scrollbars.Properties and Events
The following is a list of notable properties and methods for the scrollbars:
Min – Specifies the minimum value for the scrollbar (defaults to
0)
Max – Specifies the maximum value for the scrollbar (defaults to
500)
Value – The current value of the scrollbar based on the position
of the thumb/scroll box
LargeChange – The amount that is added or deducted from the scrollbar’s
value when the area between the thumb/scroll box and the scroll arrows is clicked
SmallChange – The amount that is added or deducted from the scrollbar’s
value when the scroll arrows are clicked
Change() – This event/method is fired whenever the value of the scrollbar
changes
Scroll() – This event/method is fired whenever the user is moving
the thumb/scroll boxWhen placing the scrollbar classes in a container (form or whatever), you can resize
the scrollbar making it wider and/or longer. The result at design time may look a
little odd (since the scroll arrows and thumb/scroll box don’t resize or reposition
themselves at design time, but everything will shape up at runtime. The point is,
that you needn’t spend a bunch of time making the scrollbars look good at design time.
Just place them, resize and position the main container and run it.Future Work and Colors
Currently the scrollbars are blue (to match Windows XP theme), but I have
my eye towards eventually allowing the scrollbar classes color to be changed either
with a single property setting or by checking the user’s current system settings and
pulling the color from there. I painstakingly created these scrollbar classes without
using any image so that the colors could be easily changed on the fly without additional
image resources.I’ll also be revisiting the code and refactoring portions of it. As it is now, I am
burnt out on it (it was a rough five hours to get this thing to work and look right).
So, don’t expect a code clinic with this class… I mean it’s not horrible, but I
do need to take another pass through it before I will be happy with it.Suggestions and Bug Reports Welcome
I also want to mention that a few members of the Visual FoxPro Community
have started to provide me with feedback, bug fixes and enhancements for the stuff
I am posting here on the SPS Weblog. I want you all to know that collaboration, help,
feedback, and/or ideas are not only welcomed and appreciated, but are exactly the
reason why I post these entries. I don’t want fame or your money… I just want
to see the Visual FoxPro Community improve the state of Visual FoxPro and the overall
experience for developers that are working in it or companies that may be considering
it as a viable option. It is my belief that one of the greatest data-centric development
tools ever created deserves nothing less.Here is the download link for the example project and vfpscrollbar.vcx source as well
as a screen shot of the example that shows the scrollbars being used in the scrollable
container class.Download VFP Scrollbars
Example and Source (46 KB approx.)
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Visual FoxPro Random License/Serial Generator
Real World Examples
In my
last blog entry I mentioned being able to use the vfpencryption.fll in some real
world ways. While encrypting passwords and sensitve data using the ciphers, or checking
passwords and files for authenticity using hash functions are pretty well known
examples, there are others.Generating CD Licenses
What about creating software serial numbers for an application
you have developed? While I highly recommend a product like Armadillo when
you need top-notch security, a more simplified approach that is still fairly secure
can be had using a hashing function such as MD5.Phil Fresle’s Earlier Work
I remembered seeing an example
of this a few years back by a developer named Phil Fresle (back then his example
was simpler than it is now). And, since the vfpencryption.fll now supports MD5, I
thought I would revisit his example and see whether something of this nature could
be created for Visual FoxPro using the vfpencryption.fll.Here is the download link and screen shot of what I came up with.
Download VFP Key
Generator Example – source code included (80 KB approx)
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Southwest Fox – Speaking and Reporting
As Andy Kramek said in his
most recent blog entry, the conference season is upon us. I couldn’t agree more
that Southwest Fox is THE conference to go
to this year.I’ll be there and though I’m not up on the speaker’s
list yet, I will be speaking/presenting. I’ll also be covering the confererence
for the Universal Thread,
so look for good daily reports by myself and Burt
Rosen.If you can find a way to attend this conference, you should. I found some great rates
on Expedia for flight, hotel, and car packages.
That’s where I got mine anyways, and I am an avid bargain hunter.Make no mistake, Southwest Fox is going to be huge! There is going to be a much
larger than usual Microsoft presence, the speaker list is packed with the best
of the best, and I am really looking forward to meeting everyone. Make it a point
to attend if you can. The Red Bull energy drinks and late night hotel coding/collaboration
sessions will be on me!Hope to see you there
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VFP Random Password/Key Generator
Today I’m working on the Encryption/Decryption session I will give at Southwest
Fox. And, while I was on the subject, I thought it would be nice if there was
a simple way to produce random cryptography keys of a required bit length for certain
encryption algorithms. So, I decided to create one in Visual FoxPro 9.0. It took all
of about 10 minutes from start to finish and provides a pretty decent way to create
random keys. Here is the download link and the customary screen shot.Download VFP Password/Key
Generator Example and Source (29 KB approx.)
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Learning Visual FoxPro Videos
Not enough time
It’s been a week since my last entry into my blog. Between billable work,
articles that I’m writing, and getting ready for the Southwest
Fox conference, time has been an extremely precious commodity. If someone finds
a way to increase the number of hours in a day to 48 using an undocumented API call,
please let me know.Increasing interest in Visual FoxPro
As interest in Visual FoxPro increases (and it is increasing), there are
a number of developers out on the forums looking for beginner books for Visual FoxPro.
I’ve even seen a few people looking for a demo of Visual FoxPro that they can try
out before making a decision on whether to purchase it (other than an occasional public
beta, this just doesn’t happen). And regrettably, there just aren’t as many books
and resources for Visual FoxPro 9.0 as there are for some of the previous versions
of the product, and few of the books that are out there are geared toward the beginner
(KiloFox gets
my vote for the greatest VFP book ever written, but regrettably it’s not the kind
of text a beginner would find easy to understand and follow).Book idea Scrapped
I started toying with the idea of writing a book on Visual FoxPro for beginners,
but that would require an extensive commitment in time, and as I’ve said, I don’t
have a lot of time on my hands these days. I also realized that I didn’t just want
to provide information for beginners, but also for intermediate and advanced Visual
FoxPro developers. The book idea was starting to look as if it would be at least 1200
pages… so, the book idea was obviously not feasible, but that didn’t quench my desire
to provide something to the Visual FoxPro community that would perhaps be considered
useful.Screencast to the rescue
I’ve taken an interest in the videos provided at FoxCast,
and found many of them very informative and useful. There’s something about being
able to see and hear another developer make a presentation via screencast that
can’t be duplicated in a book or through a podcast.
I’m not saying that a screencast is superior in every way, it has its place just as
the other types of medium do, but what appealed to me most was the ability to relay
a large amount of information in a short amount of time.Learning Visual FoxPro is born
I’ve also listened to Andrew MacNeill talk about screencasting on the
FoxShow, as well as in an
article he wrote, and I’ve created a number of screencast for application that
I’ve developed. I’ve found it to be an incredibly easy way to train users and also
provide perspective users with a way to look at a product before they buy it. And,
Visual FoxPro is essentially just a software product like any other with developers
(especially those involved in data centric application development) as its target
audience.So, I’ve begun creating a library of videos that will not only show off Visual FoxPro’s
abilities, but will hopefully provide viewers with some useful information and insight
that can help them become better Visual FoxPro developers. The videos will
be broken down into 3 series. The 100 series (101, 102, 103…) will be for beginner-level
Visual FoxPro developers. The 200 series will be for intermediate-level Visual
FoxPro developers. And finally, the 300 series will be for advanced-level Visual
FoxPro developers.Unscripted content
The narrative for the videos is not scripted. I just have a short outline
of the subject matter I want to screencast about, open up Visual FoxPro and Go. This
provides the viewer with a raw look at how I develop in Visual FoxPro which I believe
is useful. It also allows me to create videos in the shortest amount of time possible.
It’s sort of like watching a demo
Ken Levy has done for Channel 9, except
that it’s just my screen and voice.In any event, the first video is “101: Creating a Project”. As it is in the 100 series,
it is targeted toward beginners, but some intermediate developers may still find some
of the content useful. It will walk the viewer through creating a relatively simple
Visual FoxPro project from scratch to compile. It is nearly an hour long, so I’ve
busted it up into 3 seperate .swf files. Each .swf file is about 13 MB give or take
and the loader you’ll see at the beginning will stay up until 30% of the .swf has
been loaded. In other words, if you are on Dial-up, forget it. (I did initially create
a .wmv of the video, but at an acceptable bit-rate the images and audio
were unacceptably degraded. The .swf was still smaller, with crisp images and
audio.). Below are the links to the 3 parts as well as a download link for the
source code that goes along with it. I’ll be back with more videos, including the
200 and 300 series, and feedback both positive and negative is greatly appreciated.
I have no doubt that changes will be made in certain areas as I produce more videos,
so you’re feedback is important and can help me improve the overall usefulness of
what I’m trying to accomplish here.Learning Visual FoxPro
101: Creating a ProjectPart
I (19:33)Part
II (21:06)Part
III (18:15)Download
101 Source Code (621 KB approx.)
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Goodbye Drew
I offer my sincerest
condolences to Drew’s family and friends for their loss. I wish there were more that
I could say or do. Truly a sad day. – Craig
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VFP System Tasks-like Panels
Proof of concept
The following is just a quick proof of concept, so please don’t expect coding
brilliance or even real great encapsulation in the class library. With that having
been said, I decided yesterday that I would like to create something similar to the
System Tasks panel that is shown on the left-hand side of Windows Explorer (when the
folders panel isn’t open). Now, that System Tasks panel uses a bunch of cool gradients,
handles XP Theme colors and even fades the panels out when they are collapsing…
none of which is in this proof of concept. Never-the-less, I like what I was able
to come up with in a very short amount of time using pure Visual FoxPro.Data driven
The content area of the panels in my creation is actually a grid, so the
panels can be data driven. I create a cursor with the following structure…CREATE CURSOR
crsPanel1 (imgfile c(254),
capt c(75), selected L, command c(254))>The imgfile field is the name of an image file that has been compiled
into the exe, though you could use a fullpath for that if you have an images directory
that you distribute. The next field, capt is used to designate what the caption should
be for a particular item in the panel. Selected is just a boolean field that I use
to control the underlining (via the column’s DynamicFontUnderline) of the items as
the mouse passes over them. And, finally there is a command field that will hold the
VFP script to be executed (via the ExecScript function) when the user clicks on an
item. You can find where I have built the cursors that data drive the 3 panels for
the example I’ve included in the download in the Example form’s load event. Pretty
straight-forward stuff.Possible use for the scrollable container
One of the improvements to this that I’ve been thinking of is using the Scrollable
Container I created for an earlier blog entry to allow the container that is holding
the panels (cparentpanel class) to provide a scrollbar when the stacked panels exceed
the length of the form. But, I figure that it is good enough as is to at least put
it out there and get some feedback. I recevied an email from Jonathan Clark some weeks
back suggesting that something like the interface that is used at http://www.live.com/ would
be a pretty cool thing to do with VFP. Eventually, I will encapsulate the expand
and collapse functionality and some of the other features that most panels have these
days so that it is seperate from the UI portion of this. Once that is done, creating
controls and interfaces that provide this sort of look and feel will be a piece of
cake.XP Themes – possible
future project
While I’m on the subject of things I’d like to do, I’d also like to get a
handle on XP Themes as well. Though the gradients that themes use are difficult to
mimic, it would be nice to get closer to the ability to implement some form of XP
Themes on most the controls and custom classes we are creating. VFP’s out-of-the-box
UI already looks antiquated, and since the MS Fox Team doesn’t appear to have this
sort of thing on their radar at the moment, I think it would serve us well to do something
about it. I can certainly draw most anything using GDI+, so maybe there is some things
we can do to shore this up a little.Download and screen shot
I’ll stop myself with that lest I ramble for an hour or two… Here’s the
download link and a screen shot of VFP Panels in action. NOTE: When
you run the example you’ll notice that I allow the panels to be hidden (click the
X in the top right-hand corner of the panel you want to hide). In order to re-show
a hidden panel, right-click on the dark blue container and select the hidden panel
from the Show context menu.Download
VFPPanels.vcx Source and Example (220 KB approx.)
>>
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Learning VFP 102: Scope
New Learning VFP video
I’m finally back into the swing of things, and have produced a new video
for the Learning Visual FoxPro series. In this video I explore SCOPE as it exists
in Visual FoxPro for variables, arrays, parameters, constants, procedures, and object
members. I also discuss certain Visual FoxPro commands that are scoped to the current
datasession. This video is 102, so it is in the beginners series, however I have tried
to be thorough enough in my examination of scope in Visual FoxPro that intermediates
may also come away with something of value.Upcoming Videos
Before I post the links to this new 3 part video, I thought I would take
a moment and share with you a list of things that I am considering doing videos on
in the near future. So, here they are in no particular order:- Error Handling (On Error and Try…Catch…Finally)
- Modal vs Modeless
- Reports
- Database creation
- SQL
- Views (Remote, local, Createoffline()/Use Online, etc.)
- Transactions (MAKETRANSACTABLE included)
- XML
- HTML
- Web Services
- Debugging
- Coverage Profiler
- CONFIG.FPW
- String Parsing
- Indexes (including how to effectively reindex)
- SET Commands
- Project Hooks
- Using Windows APIs
- Intellisense
- Different Controls (grid,listbox, combobox, etc.)
- Foundation classes (xmladapter, cursoradapter, reportlistener, etc.)
- Drag and Drop
- BITwise functions (bitset, bitclear, bitand, etc.)
- Bindevent
- Compiler Directives
Feedback and ideas are important
If there are items in the list above that you would like to see done first,
or if you have an idea for some Visual FoxPro subject matter that should be convered
that is not in the list, please let me know. I welcome any and all feedback regarding
the videos that I do as well as the proposed videos to be done in the near future.
I want to make sure that the subjects that the Visual FoxPro Community would like
to see covered are the ones I do first.Learning Visual FoxPro 102: Scope
For Online Viewing:
Part
I (14:15)
Part
II (17:57)
Part
III (15:43)For Offline Viewing:
Download Part1 SWF File (6.5 MB approx.)
Download
Part2 SWF File (11.5 MB approx.)
Download
Part3 SWF File (11 MB approx.)Source Code used in the video:
Download
102 Source Code (5 KB approx.)If you have any problems understanding any of the concepts presented in this video,
be sure to try out the source code that accompanies this video. While a screencast
works pretty good for imparting information, nothing can beat trying a few things
on your own and stepping through some code when trying to understand scope in Visual
FoxPro. The procedural files for this video should make it easier for you to explore
all the different aspects to this.For those of you that haven’t ever used the FoxPro Frame debugger as I did in the
video, it is available as a debug setting. Go to the Tools menu, click on Options,
and then look in the Debug page (tab). You should see a dropdown box on that page that
allows you to select it.
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Simple Bar Graphs via Grid and Backstyle_Access
Email arrives
Sue Cunningham emailed me earlier this evening and told me about a cool use
she had found for the backstyle_access technique I had explained
in an earlier blog entry. If you don’t have time to wade through that blog entry
here’s the condensed version: I showed that by using the backstyle_access method of
a control contained in a grid’s column you can do just about anything you want since
that method will fire as each visible row in the grid is painted. There really isn’t
even a need for all those DynamicWhatever methods that the MS Fox Team added to the
column object when you use backstyle_access. It allows for much more complex operations
and visual effects to be performed within the grid rows as well. Anyways, Sue emailed
me and said that she had devised a relatively simple way to produce bar graphs. Something
that looks a lot like the recent gradient bars that Calvin
Hsia blogged about (see screen
shot on Andrew MacNeill’s blog), but much simpler (no need for GDI+) and minus
the gradient.I decided to give it a try
Sue didn’t provide the code to her solution, but based on the explanation
she had given in her email, I felt I had the basic idea and decided to try my hand
at it and see what I could create. The result (see screen shot below) was as
pleasing as it was easy. Sue also said that she was encountering some unpredictable
results when placing the grid within a container control, so I also produced an example
(Example2 form in the source that can be downloaded below) that also uses this technique
to display graphs on two separate pages of a pageframe. I didn’t run into any of the
inconsistent results (using VFP 9.0 SP1 here) that Sue did, so I’m not sure what is
happening for her there. The technique appears to work flawlessly (Note: the bars
will get truncated and/or have paint problems if I allow the grid to show both panels
at the same time and the left panel is a CHANGE panel. The Change panel is the
only place I saw this unwanted behavior, other than that all is right).What all is involved
I have a grid subclass that contains two columns. The first column is used
for the description of whatever the item is I am graphing… you can think of it as
the axis label I guess. The second column contains a pretty simple container subclass
that contains a shape and a label subclass. The shape is used to produce the bars
and the label is used to show the value that was graphed. The magic for all of this
is in the container control (that is in column2) backstyle_access method. Here’s the
actual code which is quite short…LOCAL lnTotalTicks, lnValue, lnWidth
lnTotalTicks = (this.Parent.Parent.MaxValue – This.Parent.Parent.MinValue)
lnValue = EVALUATE(this.Parent.Parent.recordsource + “.value”)
lnWidth = (This.Parent.Width – 35) * (lnValue/lnTotalTicks) && – 35 to leave
room for the value caption
This.cshape1.Width = lnWidth
This.clabel1.Caption = TRANSFORM(lnValue)
This.cLabel1.Left = lnWidth + 5 && leave a five pixel margin
RETURN THIS.BackStyleThat’s basically all there is to it. The bars will be whatever color the shape is
in the container. You could admittedly improve on what I am providing here by adding
a barcolor property for the grid or perhaps showing the bars in different rows in
different colors based on some criteria, or by calling a method of the grid from the
container’s backstyle_access so that bit of code above isn’t so hidden. I am just
providing the basic premise here, this is certainly not a finished product with all
the bells and whistles that are possible. Also, as you’re looking at the examples
you may notice that there are MinValue and MaxValue properties that have been
added to grid subclass. These are so we don’t have to always graph on 0 – 100 or whatever
(see code above). The values graphed could be anything, say 1000-10000 or whatever.Finally, to see the very simple cursors that the bar graph grids run off of, look
in the example forms’ load events where you’ll find something like thfollowing code…LOCAL lnCounter
CREATE CURSOR crsValues (Descript c(25), Value I)
=RAND(-1)
FOR lnCounter = 1 TO 100
INSERT INTO crsValues (Descript, Value) VALUES (“Item ” + TRANSFORM(lnCounter),
INT(100 * RAND( ) + 1))
ENDFOR
GO TOP IN crsValuesAs you can see the cursor that is needed for this is extremely simple, just two fields
in fact, one for the description and the other for the values. In any event, this
just once again shows the value of Visual FoxPro’s grid class when coupled with the
backstyle_access method. With very few lines of code we are able to produce a pretty
useful class for visually displaying data to our users. Thanks for the emailed tip Sue
and it was a pleasure meeting you at Southwest Fox 2005!Source Code and Screen Shot
When you get the zip file downloaded, extract the contents. Open the project
in Visual FoxPro and run the Example and Example2 forms.Download Grid Graph
Source Code with Examples (23 KB approx.)
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Bar Graphs – Part II
Improving on yesterday
In yesterday’s
blog entry I showed a technique that could be used to create simple bar graphs.
There was one thing missing from the bars on the graphs however, gradients. In
any event, I decided to try my hand at a solution similar to the
one shown by Calvin Hsia, but without all the quirky behavior that renders Calvin’s
example fairly unusable in a real-world application (to be fair, his was more
of a proof-of-concept than anything).Gradient Bars
If you want gradients in your Visual FoxPro applications and don’t want to
have to go through some of the machinations that I did for the progressbar control
I showed in an
earlier blog entry, then you are going to have to use GDI+. The combination of
GDI+ and the backstyle_access method of an object contained in a grid’s column gives
us everything we need to produce some first-class results.In the solution that I am showing here I use a grid subclass and an image subclass
to display the bars. That’s it as far as the classlib is concerned, but if you look
in the grid’s Init event and its Drawbar and Drawtext methods you’ll see that
there is some fairly heavy reliance on GDI+ and subsequently the _gdiplus.vcx class
library that is shipped with Visual FoxPro 9.0. Given the complexity of GDI+ code
to those who may be unfamiliar with it, I have heavily commented the code for this
solution. I encourage you to read through it. I am hoping that it will be clear what
I am doing and why.Annoying Picture property behavior
One thing I’ve run into when working with GDI+ in Visual FoxPro is the fact
that Visual FoxPro will bring up a busy cursor (hourglass) when the picture property
of a container or image is set (perhaps other classes as well). This means that when
I am using an off-screen bitmap to draw to and I set that bitmap’s fullpath as the
Picture property that the mouse cursor will change back and forth from an arrow to
an hourglass to an arrow to an…. you get the idea. In a perfect world the Microsoft
Fox Team would let us as developers determine when a mouse cursor should show busy,
or at the very least allow us a way to shut off this helpful “feature”, but that’s
not the case here. Luckily they didn’t do the same thing when they implemented the
PictureVal property of the image control. So, in order to get rid of this flickering
mouse, I use an image control and after I have written the bitmap to disk I convert
it to a string with FILETOSTR() and use it for the PictureVal. Works like a charm,
even if there is no doubt some additional overhead with this approach.Improved grid subclass
I spruced up the grid subclass a bit and provided additional properties that
can be set to change the gradient colors (Gradientcolor1 and Gradientcolor2 properties),
as well as a GradientDirection property that can be set to change the direction in
which the gradient is drawn (Horizontal = 0, Vertical = 1, Forward Diagonal
= 2, Backward Diagonal = 3). I’ve also placed the code that is used to
draw the bars in a Drawbar method of the grid subclass. This Drawbar method is called
by the image subclass (that is contained in column2) backstyle_access method. And
finally, since I was already using GDI+, I decided to forego an additional label object
and instead I draw the value text at the end of each bar using GDI+. The font that
is used for the value text is the same as has been set for the column1 descriptions,
so if you change column1’s font it will change the font used to render the
value text as well.Additional improvements possible
There are a number of improvements/enhancements that could no doubt be made to this
solution. Some that I can think of would be to allow the developer to define the fields
that are to be used for the descriptions and values rather than hardcoding it to a
particular cursor/table structure. Another improvement would be to allow for drill-downs
in some fashion so the user could double-click on a particular row and be presented
with the group of data that made up that particular value. Given that this is using
pure GDI+ to draw the bar nearly anything could be drawn there and if the rows had
a tall enough height individual pie slices could be shown. This might look really
good on a form where the grid is shown next to the entire pie chart.I also cut some corners when it came to the rendering of the value text. The height
of that text for centering is determined from the form’s textheight method which could
lead to erroneous results. I also didn’t completely duplicate the font being used
by column1, things such as bold or underline or strikethru have been ignored. However,
to my credit I did provide the additional constants and such that are needed should
you wish to go further with this. I felt that what I had was good enough for this
blog posting and I don’t know if I would want the value text to be underlined or whatever
even if the developer decided to do that themselves. I guess if I was thinking I would
have taken all the values from column2’s font settings (the column that the bars are
actually rendered in) and used that… it would have provided a simple and intuitive
way for the developer to determine the font used for the value text that is rendered
at the end of each bar. I guess I wasn’t thinking, but hopefully you get the idea
here which is what I’m striving for.Future ideas
Sue Cunningham is at it again and has emailed me about the next phase of
her solution which will be to provide the users with a way to print the bar graph
that is shown in the grid. I’ll let that roll around in my head for a day and see
what occurs to me. I’m thinking that task just got a lot easier with this solution
since I’m using GDI+ and the _reportlistener is kind enough to expose the GDI+ Graphics
object(s) it is using when it renders a report. Seems like I’ve already got most of
the pieces… just need to move it from a grid subclass to a _reportlistener subclass.
Thanks again Sue, I think you’ve given me another future topic with your email.Source Code and Screen Shots
When you get the zip file downloaded, extract the contents. Open the project
in Visual FoxPro and run the Example and Example2 forms.Download the Gradient
Graph and Examples (63 KB approx.)
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Learning VFP 104: Error Handling
New Learning VFP video
This video is on the topic of Error Handling. A far too often overlooked
aspect of software development that is absolutely critical to creating great applications.
Error handling in Visual FoxPro runs the gamut, from the familiar ON ERROR command
used for procedural error handling, to the fairly new Try…Catch…Finally structured
error handling. Visual FoxPro offers a surprising number of choices and solutions
when it comes to error handling. Find out the strengths and weaknesses of each through
this 3 part video. Beginners can expect to get a handle on the basics and intermediates
might learn a few things about some of the more obscure stuff such as the COMRETURNERROR
function for use in COM servers.Video Timeline
A suggestion was made after my
last video that I provide a timeline detailing the contents of the Learning VFP
videos so that viewers can quickly find what they are looking for. I also think it
helps viewers know what they can expect to learn in the videos, so here is the timeline/guide
for this 3 part video series on error handling…Part1 – Total Length 25:05
00:00 Introduction
01:05 Basic ON ERROR command use
05:47 Conditional error handling with ON ERROR command
08:33 Use of RETRY
10:38 Use of AERROR() to retrieve error info
15:00 Throwing an exception using ERROR command
19:53 Use of ASTACKINFO() to retrieve call stack infoPart2 – Total Length 33:20
00:00 Basic Try…Catch…Finally use
07:55 Conditional error handling with Try…Catch
12:10 User-defined errors and exception subclassing
21:42 Nesting Try…Catch…Finally blocks
25:20 Exception escalation using ThrowPart3 – Total Length 29:32
00:00 Creating a user-friendly error form and emailing errors
10:48 The Error Event and overall error handling priority
17:48 Using the COMRETURNERROR command in COM Servers
28:40 Wrap-upLearning Visual FoxPro 104: Error Handling
For Online Viewing (same content as offline version):
Part
I
Part
II
Part
IIIFor Offline Viewing (same content as online version):
Download Part1 SWF File (13.3 MB approx.)
Download
Part2 SWF File (16.2 MB approx.)
Download
Part3 SWF File (19.4 MB approx.)Source Code used in the video:
Download
104 Source Code (198 KB approx.)If you have any problems understanding any of the concepts presented in this video,
be sure to try out the source code that accompanies this 3 part video series. While
a screencast works pretty good for imparting information, nothing can beat trying
a few things on your own and stepping through some code when trying to understand
scope in Visual FoxPro. The files included in the source download for this video series
should make it easier for you to explore all the different aspects of error handling
in Visual FoxPro.NOTE: I haven’t forgotten Learning VFP 103. It’s on the way, I just haven’t had time
to finish it yet.
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A Regular Expressions library for Visual FoxPro
What are Regular Expressions?
Rather than spend thousands of keystrokes explaining what regular expressions
are, here’s what the Wikipedia
has to say.How can they be used in Visual FoxPro?
The main way in which VFP developers have utilized regular expressions (if
at all) in their applications is via the Windows Scripting Host. You can see some
more information on regular expressions and how
the RegExp object is used in VFP code on the Fox.Wikis (Thanks to Alex
Feldstein for most of the content).While this solution is OK, there are a few gotchas such as the user account’s security
settings getting in the way, or WSH not being available on the system. However, it
is the best most of us could do if we didn’t have some spendy third party library
to provide this functionality. But then I decided to try my hand at creating another
solution that we could all benefit from.Introducing the regexp.fll
I decided it was high time that Visual FoxPro developers had a free Visual
FoxPro Dynamic-Link Library (FLL) that would provide for regular expressions in Visual
FoxPro, so I sat down at my copy of Visual Studio 8 and, with the help of Boost,
I wrote one. Unfortunately the process wasn’t quite as straight forward as that last
sentence makes it sound.First I toyed with the idea of writing my own in pure Visual FoxPro code. That bad
idea, while appealing to my reinvent the wheel side, was soon discarded because it
would be too much effort and the end result would never be able to match the performance
that could be achieved by doing this in C++. Next I researched all of the available
C++ libraries that were available and for a time I was using GRETA,
but between bugs in the code, the feeling that it wasn’t being supported quite as
well since Eric Niebler left, and some disturbing things I read about the licensing
regarding commercial applications, I soon discarded this as well.After playing around with a half-dozen other libraries and comparing form, function,
and performance of each I settled on Boost
RegExp and the regexp.fll project took shape and was finished in short order.
It probably took me as long to compile the Boost RegExp libraries as it did to write
the actual code for this FLL.Just a start
This library currently just does matching. While matching is arguably the
thing regular expressions are used for most, there are a lot of other things that
I will be adding to this library that will allow us to do a whole host of things in
Visual FoxPro using regular expressions, such as return match sets, perform positional
searches, and do replacements. Even though the library doesn’t provide for this other
functionality, I think you will find its current matching capabilities pretty useful.Important note about the required C++ runtime libraries
In order to use this FLL (which was compiled with Visual Studio 8), you will
need the correct runtime libraries and they have to be placed on the system in a very
specific way. I can’t tell you the number of emails I’ve gotten for the
vfpencryption.fll that I wrote where developers were having problems getting it
to work because they didn’t have the runtimes or the runtimes weren’t installed on
the system correctly. I’m not saying I minded the emails (it’s always good to hear
from a member of the Visual FoxPro Community), or that I don’t understand the confusion…
I’m just saying that with Visual C++ 8.0 some of the rules have changed and we all
have to learn the correct way to go about doing this in the age of .NET 2.0.The easiest way to get the correct C++ runtime libraries installed on your system
(or a user’s system) is to just download
the installer (2.48 MB) that Microsoft has provided. It has some bloat to it,
but it is point and click easy and the libraries all get installed where they should
be without much hassle or fuss.Now, for those of you that want to create install sets or just want to have the bare
minimum required you will want to create a subdirectory named “Microsoft.VC80.CRT”
in the same directory that the regexp.fll is in. The Microsoft.VC80.CRT subdirectory
needs to have 4 files in it: Microsoft.VC80.CRT.manifest, msvcm80.dll, msvcp80.dll,
and msvcr80.dll. In order to help you set this up I have created a
zip file of this folder (577 KB) that you can download. You don’t have to register
any of these files or do anything additional other than provide them as I have specified
here. The directory structure should look like this…
As you can see, both the Microsoft.VC80.CRT and regexp.fll are in the same directory
(My Application). And, inside of the Microsoft.VC80.CRT subdirectory are the previously
mentioned 4 files. This is the way to do this for any FLL that I release. (truth be
told there are other ways to do this, but then I have to go into a whole discussion
about the WinSxS directory and what to do on pre-XP versions of Windows… life is
too short)Using the regexp.fll in Visual FoxPro
The first thing to do is download the FLL at the link provided at
the bottom of this blog entry and make sure that you have the C++ runtimes
installed as described in one of the two ways above. Then you can start using
it from within Visual FoxPro or your Visual FoxPro applications. The syntax is very
straightforward and there is only one function to remember… RegExp(cString, cRegExpression). The
cString parameter is the string you want searched for a match, and the cRegExpression
is the regular expression you want used when matching. RegExp() will return .T. for
a match and .F. for no match. It might help to see some simple coded examples (cut-n-paste
the code below into a prg and execute it)…CLEAR
*!* Let Visual FoxPro know about the new function
*!* by setting the library to the regexp.fll
SET LIBRARY TO LOCFILE(“regexp.fll”,”FLL”,”Locate regexp.fll”)LOCAL lcExpression
*!* Validate Email addresses
lcExpression = “^([0-9a-zA-Z]+[-._+&])*[0-9a-zA-Z]+@([-0-9a-zA-Z]+[.])+[a-zA-Z]{2,6}$”
?RegExp(“john@isp.com”,lcExpression)
?RegExp(“john@.isp.com”,lcExpression)*!* Validate currency amounts
lcExpression = “^(\$)?(([1-9]\d{0,2}(\,\d{3})*)|([1-9]\d*)|(0))(\.\d{2})?$”
?RegExp(“$1,244,311.81”,lcExpression) && Match
?RegExp(“$1,24,4311.81”,lcExpression) && No Match*!* Validate days of the week
lcExpression = “^(Sun|Mon|(T(ues|hurs))|Fri)(day|\.)?$|Wed(\.|nesday)?$|Sat(\.|urday)?$|T((ue?)|(hu?r?))\.?$”
?RegExp(“Sunday”,lcExpression) && Match
?RegExp(“sundae”,lcExpression) && No Match*!* Validate phone numbers
lcExpression = “^[2-9]\d{2}-\d{3}-\d{4}$”
?RegExp(“507-562-0020”,lcExpression) && Match
?RegExp(“507-56-0020”,lcExpression) && No Match*!* release the library reference
SET LIBRARY TOBoost documentation for RegExp
You can find the documentation
for the RegExp’s syntax on the Boost website (you’ll note that it is based on
the Perl regular expression syntax). You can also find a whole host of other examples,
information and how-tos for regular expressions by doing a quick web
search.Here’s the link to download the regexp.fll
I’ve included the Boost license as a ReadMe.txt with this FLL. It isn’t necessary
to distribute this disclaimer with the FLL as the FLL is a compiled library, however
I am including it so you can see what the license says – the basic point is that we
are free to use this commercially. If you want more information on the license
requirements for Boost.Download the regexp.fll (47
KB approx)
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VFP foxhead logo is a trademark
Craig Berntson raises an issue
Earlier today Craig Berntson wrote a
short blurb on his blog raising the concern that the VFP foxhead logo (morphfox.gif) and
music I am using in the Visual FoxPro promo
video #1 and promo
video #2 was infringing on copyrights and/or trademarks. I didn’t see Craig’s
blog entry until I received an email from Microsoft telling me that the VFP foxhead
logo was indeed a non-redistributable logo trademark that I needed to remove from
my website.Copyrights/Trademarks matter to me
As anyone who has downloaded any of my derivitative works knows, I strive
hard to protect individual property rights and/or give credit where credit is
due. In the interests of protecting and respecting others’ rights, I have replaced
the VFP foxhead logo with two Microsoft approved logos in the promo videos. I have
also replaced the soundtrack on promo video #2 with a royalty free copy of “Also Sprach
Zarathustra” (a.k.a. the theme for 2001: A Space Odyssey) that I purchased. The soundtrack
for video #1 is already a royalty free loop. I have also begun the process
of removing the VFP foxhead logo from other places it appears in my code samples,
screen shots, and the Learning Visual FoxPro videos. As some of these tasks are somewhat
large, Microsoft has been kind enough to provided me with additional time to complete
the removal. In any event, when you view the newest versions of the promo videos online
you should NOT see the VFP foxhead logo.Important Note: Those of you that have already viewed
the VFP promo videos may still have the older versions in your browser cache. In order
to see and use the new videos you will need to delete these SWF files from the cache.
Alternately, you can download the zip files and view them offline. I apologize for any inconvenience
this may cause you.Microsoft has provided alternate logos for use
I am providing copies of both of the logos that we can use in lieu of the
VFP foxhead logo for anyone who may be interested in them. Download VFP9_Boxshot.jpg and Boxshot_VFP9.jpg.
These are images of the Visual FoxPro CD case that has the foxhead logo on it (see
bottom of this entry). It is my understanding that we are allowed to use these images
as is. It is also my understanding that we can’t modify them other than simply resizing
them, but we can use them on our websites or in videos such as I created.I like these logos and really appreciate that they have been provided. I would even
go so far as to say that the promo videos look better with these logos in them as
it gives the viewer a better sense for what exactly is being promoted.In the future
Should you come across any material on this site that you believe is infringing
on someone’s rights – copyright, trademark, or otherwise – I would appreciate
it if you would contact me directly as soon as possible via email or
phone (both are listed on the SweetPotato
Software website). I will work quickly to rectify the problem once I know
about it. Thanks to Craig Berntson and Microsoft for the heads-up regarding these
problems.
It is my understanding that these two logos are the ones that developers may use in
lieu of the VFP foxhead logo (morphfox.gif).
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Creating our own Fox logos
Now here’s an idea
Bill Sanders announced (in a comment to a recent
blog entry I made) that he is funding graphic artists to create 3-5 Fox logos
that the VFP Community can use. The reason for this is that the Foxhead logo, that
comes with Visual FoxPro 9, is a Microsoft trademarked logo that they are not giving
us permission to use by itself. It can only be used as it is in the image of the Visual
FoxPro 9.0 CD case. In any event, I’m excited by the prospect of these new logos and
I can’t wait to see what Bill comes up with.My own stab at it
I’m not a professional graphic artist but, intrigued by Bill’s idea of rolling
our own, I decided to try my hand at creating a logo. I wanted something dark, to
match the Visual FoxPro 9.0 CD case, and I wanted it to be a fox’s head. With those
two goals in mind, the following is what I came up with. A little too menacing
perhaps?
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Hosting a .NET ActiveX Control in Visual FoxPro
Not Supported
Creating ActiveX controls in Visual Studio 2005 for use in Visual FoxPro
is not officially supported by Microsoft. Now with that out of the way, let’s see
what we can do (see screen shots at the bottom of this blog entry).Superior + Superior = 2XSuperior
Visual FoxPro is generally superior to .NET in working with data. .NET is
generally superior to Visual FoxPro when it comes to controls and visual eye candy.
So, the idea is to marry the two and enjoy the benefits that each has to offer. Now
before either side starts flaming me about how VFP can be visually appealing or .NET
can work with data, you should know that I don’t care (LOL). The arguments are played
out, and a waste of time. Better to spend our time sharing really cool code, extending
Visual FoxPro in every way possible, and getting ready for Sedna.Great articles on this topic
There are some really good articles about .NET interop that will hopefully
help those of you not familiar with the topic to come up to speed. The first three
links are articles that were done by Rick Strahl and relate specifically to .NET interop
as it pertains to Visual FoxPro. The last two articles were the basis for what I’m
about to show.-
Passing
objects between FoxPro and .NET COM Components -
Handling
.NET Events in FoxPro via COM Interop -
Creating
multi-threaded components .NET for COM Interop with Visual FoxPro -
HOW TO: Sink
Managed C# Events in Internet Explorer Script -
Exposing
Windows Forms Controls as ActiveX controls
Adventures of trying to create a .NET UserControl for use in Visual
FoxPro
One of the things that I like about .NET is its toolstrip and menustrip controls,
and given the popularity of the ARG-Software’s Command
Bars Library among Visual FoxPro developers I’d say I’m not the only one.
They’re just really professional looking. So, I decided that I wanted to create a
menustrip and a toolstrip in Visual Studio .NET and use it on a Visual FoxPro form.
The first thing I ran into was a bunch of information on the internet that said it
wasn’t possible to create a visual ActiveX control in .NET and use it in an environment
like Visual FoxPro or Visual Basic 6.0. But as the search continued, I finally uncovered
the page that is link #5 in the list above.So it is possible. Next thing to work out was how to get events to fire over in Visual
FoxPro. Unfortunately I ran into the page that is link #4 above before I ran
into Rick Strahl’s article on it (link #2 above). Oh well, while Rick’s article would
have saved me some time, it was fairly straight forward to implement looking at the
steps and C# code at link #4 above even if the content was not purported to be for
Visual FoxPro. Same concept, same end result.Abridged version of what to do in C#
- Create a new Class Library project that consists of a UserControl
- Throw a toolstrip and a menustrip in your UserControl
- Set the modifier property for each to Public so you can see them from Visual FoxPro
-
At the top of your source file add the following using statments:
using System;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Reflection;
using Microsoft.Win32;
-
In the namespace block of your control code define delegates for
the events like this:
namespace DotNetControl
{
[ComVisible(false)]
public delegate void MyClick1EventHandler();
[ComVisible(false)]
public delegate void MyClick2EventHandler();
…
-
Define a public interface to expose the events of your UserControl
class in Visual FoxPro like this (Notice the Guid, InterfaceType, and DispId attributes
– you’ll need to generate your own Guid):
[GuidAttribute(“F11EC17C-59E1-42D1-AE96-712AB79F20AB”)]
[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIDispatch)]
public interface ControlEvents
{
[DispIdAttribute(1)]
void MyClick1();
[DispIdAttribute(2)]
void MyClick2();
} -
The beginning of your class definition should look something like
the following (Notice the Guid, ProgId, ClassInterface and ComSourceInterfaces – generate
your own Guid and make sure the parameter sent to typeof is the same as
the public interface you created in step 6) :
[Guid(“2DEFE6F9-6738-454C-BEF1-CF944E7F5F06”)]
[ProgId(“DotNetControl.DotNetToolbar”)]
[ClassInterface(ClassInterfaceType.AutoDual), ComSourceInterfaces(typeof(ControlEvents))]
public partial class DotNetToolbar : UserControl
{
public DotNetToolbar()
{
InitializeComponent();
}
…
-
Specify your events
event DotNetControl.MyClick1EventHandler MyClick1;
event DotNetControl.MyClick2EventHandler MyClick2;> -
In the designer double-click on the controls that you are exposing events for and
you will end up with some method code blocks like the following being added (Notice
I have added some simple if condition blocks to call the events we defined in
step #8) :private void myToolStripButton_Click(object sender, EventArgs e)
private void myToolStripMenuItem_Click(object sender, EventArgs e)
{
if (MyClick1 != null)
{
MyClick1();
}
}
{
if (MyClick2 != null)
{
MyClick2();
}
}>
> -
Override the Dispose method:
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (components != null)
components.Dispose();
}
base.Dispose(disposing);
}>
>> -
Add the following method to your class (Notice since it has been attributed with ComRegisterFunction
this code will fire when the assembly is registered for COM interop)
//copyright Morgan Skinner, 2001
[ComRegisterFunction()]
public static void RegisterClass(string key)
{
// Strip off HKEY_CLASSES_ROOT\ from the passed
key as I don’t need it
StringBuilder sb = new StringBuilder(key);
sb.Replace(@”HKEY_CLASSES_ROOT\”, “”);
// Open the CLSID\{guid} key for write access
RegistryKey k = Registry.ClassesRoot.OpenSubKey(sb.ToString(), true);
// And create the ‘Control’ key – this allows it
to show up in
// the ActiveX control container
RegistryKey ctrl = k.CreateSubKey(“Control”);
ctrl.Close();
// Next create the CodeBase entry – needed if not
string named and GACced.
RegistryKey inprocServer32 =
k.OpenSubKey(“InprocServer32”, true);
inprocServer32.SetValue(“CodeBase”, Assembly.GetExecutingAssembly().CodeBase);
inprocServer32.Close();
// Finally close the main key
k.Close();
}> -
Add the following method to your class (Notice since it has been attributed
with ComUnRegisterFunction this code will fire when the assembly
is unregistered)//copyright Morgan Skinner, 2001
[ComUnregisterFunction()]
public static void UnregisterClass
( string key )
{
StringBuilder sb = new StringBuilder (
key ) ;
sb.Replace(@”HKEY_CLASSES_ROOT\”,“”)
;
// Open HKCR\CLSID\{guid} for write access
RegistryKey k = Registry.ClassesRoot.OpenSubKey(sb.ToString(),true);
// Delete the ‘Control’ key, but don’t throw an
exception if it does not exist
k.DeleteSubKey ( “Control” , false )
;
// Next open up InprocServer32
RegistryKey inprocServer32 =
k.OpenSubKey ( “InprocServer32” , true )
;
// And delete the CodeBase key, again not throwing
if missing
k.DeleteSubKey ( “CodeBase” , false )
;
// Finally close the main key
k.Close ( ) ;
} -
In your solution’s properties do the following:
- Checkmark the “Register for COM interop” checkbox on the Build page
-
Checkmark the “Make assembly COM-visible” checkbox in the Assembly Information screen
accessible from the Application page (alternately you can just open up the AssemblyInfo.cs
file and make sure it says:
[assembly: ComVisible(true)]
After you’ve completed these steps, you can build your assembly and you should have
a useable ActiveX control for use in environments such as Visual FoxPro and Visual
Basic 6.0. You may see some warning regarding non COM visible value types during the
build, but there shouldn’t be any errors and the assembly should be in your bin directory.
If you get stuck on any of the steps above, you can always refer to C# solution I
am including in the download at the bottom of this page.How to use the ActiveX in Visual FoxPro
Once you have built your ActiveX control you can then proceed to use it in
Visual FoxPro. If you aren’t building the control (which will register the control
for COM interop on your system) and just want to use one like I made, you’ll have
to register the DLL with REGASM.
The same holds true for when you distribute the control. You’ll either need to include
it in an installer package that was created with a program that understands how to
register .NET assemblies or you’ll have to use regasm on the user’s system. If you’ve
never heard of Regasm before this, you can think of it as very much like RegSvr32.In any event, for the control that I’ve created you’ll want to follow the following
steps in Visual FoxPro:- Make sure the .NET assembly (DLL) has been registered on your system
-
Go to Tools->Options and on the resultant Options screen go to the Controls page,
select ActiveX and scroll down through the list of ActiveX controls until you find
the .NET control you want. In the case of the control I built, it will be named DotNetControl.DotNetToolbar.
Place a checkmark next to it and then click OK -
Create a new form and on the Form Controls toolbar click the View Classes dropdown
button (looks like library books) and select ActiveX controls. -
Select the button that is provided for the DotNetToolbar and place an instance of
it on your form -
Resize and position the resultant menu/toolbar at the top of your form and set its
Anchor property to 11. -
Go into the methods of the control and add whatever code you want to the ToolClick
and MenuClick events (such as toolnewclick, toolsaveclick, menuexitclick, menuhelpclick,
etc.) - Run your form.
I am providing a sample form in the download for this blog entry. I haven’t done much
with those events except add messageboxes to show that they fire. Also, I’ve provided
an optiongroup that will set the RenderMode of the toolstrip and menustrip just to
show that we aren’t limited to events that we have exposed through the interface.
Public objects and their properties are accessible as well.Just the beginning of what’s possible
In this blog entry I am merely showing that it is possible to create .NET
ActiveX controls for use in Visual FoxPro. More is possible, such as starting with
an empty menustrip and empty toolstrip and allowing the Visual FoxPro developer to
add items to the .NET controls dynamically. Plus, the toolstrip and menustrip are
but two examples of many other controls that could be made for use in Visual FoxPro.
Extending Visual FoxPro by utilizing the .NET framework is powerful, and the chief
reason I wholeheartedly support the Sedna initiative put forward by the Micorosft
Fox Team. It was, in my opinion, the right decision based on the resources available
and the benefits to be gained. Coupling Visual FoxPro’s unmatched data handling abilities
with the best that .NET has to offer is a very powerful combination.Source download and the screen shots
Download
Source and Example VFP Form (51 KB approx.)Note: In the download the example form is contained in the VFPExampleForm subdirectory
and the .NET control is contained in the bin\Release subdirectory. The .NET control
MUST be registered using Regasm before you can run the VFP example form.
.NET menustrip and toolstrip look professional
Menus have great theme support
Resizing the form will cause toolstrip to show dropdown button
Using the optiongroup the RenderMode can be changed
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Visual FoxPro on Windows Vista
Windows Vista is on it’s way
Many
are speculating that Microsoft is doing whatever it takes to get their newest OS
released before the end of 2006. It won’t be long and Visual FoxPro developers
will be catering to customers running Windows Vista. Microsoft’s Visual
FoxPro Roadmap has Sedna currently scheduled for release sometime around the 2Q
of 2007. This could lead some Visual FoxPro developers to be somewhat alarmed as one
of the things that Sedna will provide is the ability for Visual FoxPro applications
to be more successfully deployed on Windows Vista.Seems to work fine
In order to ascertain just what kinds of problems we are going to run into
deploying and running Visual FoxPro 9.0 applications on Windows Vista without Sedna,
I decided to give it a go. I installed Windows Vista Beta 2 – Build 5231 on a
Windows XP Professional box using Microsoft’s
Virtual Server 2005. Then I installed a copy of Visual FoxPro 9.0 SP1 into Windows
Vista and started playing around with it. While it will be sometime before I
can make a final determination regarding the complete viability of deploying Visual
FoxPro 9.0 applications on Windows Vista, for now I am quite pleased with how well
Visual FoxPro appears to run and act in Windows Vista. I’ll report back with more
once I have had the time to take a closer look. For now, here’s a screen shot of Visual
FoxPro running like a top on Windows Vista.NOTE: Given that I am using Microsoft’s Virtual Server,
the Aero Glass effects are not enabled because the graphics card emulator doesn’t
support them. This is not a limitation of Visual FoxPro, but rather a limitation of
the environment in which I am hosting Windows Vista.
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Change Mouse Cursor
Setting the System Cursor
Someone out on the Universal Thread was
asking how to set the mouse cursor to a string of text. Doing this is pretty straight-forward
with GDI+ and Visual FoxPro 9.0. The following runnable example will save the current
mouse cursor icon and then change it to the string “VFP ROCKS!”. It will also allow
you to select an image file to use as your mouse cursor, which is really the technique
that makes the previous string example possible. Finally, after the two examples have
run it will set your mouse cursor back the way it was (saving a trip into Control
Panel -> Mouse). Just cut-n-paste the following code into a PRG file in Visual
FoxPro 9.0 and execute it.IMPORTANT NOTES: The active portion of the cursor is the
center of the image. Images for the second example aren’t limited to icons only, most
other image formats are supported. But, be careful how big the image is you select
for the 2nd example. I was dragging around a huge screen shot as my mouse cursor at
one point… it makes it a little difficult to click on things. LOL
LOCAL
lnPreviousIconHandle, lnNewIconHandle, lcImageFile, loExc as Exception
*!* Save
the current icon handle so we can set it
back
m.lnPreviousIconHandle = GetCurrentCursorHandle()
IF m.lnPreviousIconHandle
!= 0
TRY
m.lnNewIconHandle = GetHICONFromString(“VFP
ROCKS!”, 0, 0, “Arial”,
12, 1, 3, RGB(255,0,0),
255, 0)
IF m.lnNewIconHandle
!= 0
SetSystemCursorToHICON(m.lnNewIconHandle)
ENDIF
MESSAGEBOX(“Click
OK when you are ready for the next example.”)
SET DEFAULT TO (ADDBS(HOME(4)) + “Icons\Computer\”)
m.lcImageFile = GETPICT(“”,“Select
an image file”, “Select”)
m.lnNewIconHandle = GetHICONFromImage(m.lcImageFile)
IF m.lnNewIconHandle
!= 0
SetSystemCursorToHICON(m.lnNewIconHandle)
ENDIF
MESSAGEBOX(“Click
OK when you are ready to return the cursor to its orginal image.”)
CATCH TO loExc
*!* Ooops!
FINALLY
*!* Set icon
handle back to the
way it was
SetSystemCursorToHICON(m.lnPreviousIconHandle)
ENDTRY
ENDIF***************************************
Function GetCurrentCursorHandle()
***************************************
LOCAL lnReturn
DECLARE INTEGER CopyIcon IN Win32Api INTEGER
DECLARE INTEGER GetCursor IN WIN32API AS _GetCursor
*!* Save
current cursor so we can restore it
m.lnReturn = CopyIcon(_GetCursor())
CLEAR DLLS “CopyIcon”, “_GetCursor”
RETURN (lnReturn)
ENDFUNC***************************************
FUNCTION SetSystemCursorToHICON(tnIconHandle,
tnCursorStateToSet)
***************************************
*!* Defines
are provided so you‘ll
know
*!* what‘s
available
#define OCR_NORMAL 32512
*!* #define
OCR_IBEAM 32513
*!* #define
OCR_WAIT 32514
*!* #define
OCR_CROSS 32515
*!* #define
OCR_UP 32516
*!* #define
OCR_SIZE 32640 /* OBSOLETE: use OCR_SIZEALL */
*!* #define
OCR_ICON 32641 /* OBSOLETE: use OCR_NORMAL */
*!* #define
OCR_SIZENWSE 32642
*!* #define
OCR_SIZENESW 32643
*!* #define
OCR_SIZEWE 32644
*!* #define
OCR_SIZENS 32645
*!* #define
OCR_SIZEALL 32646
*!* #define
OCR_ICOCUR 32647 /* OBSOLETE: use OIC_WINLOGO */
*!* #define
OCR_NO 32648
*!* #define
OCR_HAND 32649
*!* #define
OCR_APPSTARTING 32650
IF PCOUNT() = 1
m.tnCursorStateToSet = OCR_NORMAL
ENDIF
DECLARE SetSystemCursor IN Win32Api INTEGER, INTEGER
SetSystemCursor(m.tnIconHandle,m.tnCursorStateToSet)
CLEAR DLLS “SetSystemCursor”
ENDFUNC***************************************
Function GetHICONFromImage(tcImageName)
***************************************
LOCAL lnIconHandle, lnBitmap, lnReturnSTORE 0 TO m.lnIconHandle,
m.lnBitmap, m.lnReturnDECLARE INTEGER GdipCreateBitmapFromFile IN GDIPLUS.DLL
;
STRING wFilename, INTEGER @
nImage
DECLARE LONG GdipCreateHICONFromBitmap IN GDIPLUS.DLL
;
INTEGER nBitmap, INTEGER @hbmReturnIF !EMPTY(tcImageName)
GdipCreateBitmapFromFile(STRCONV(m.tcImageName+CHR(0),5),
@m.lnBitmap)
IF m.lnBitmap
!= 0
GdipCreateHICONFromBitmap(m.lnBitmap,
@m.lnIconHandle)
IF m.lnIconHandle
!= 0
m.lnReturn = m.lnIconHandle
ENDIF
ENDIF
ENDIF
CLEAR DLLS “GdipCreateHICONFromBitmap”, “GdipCreateBitmapFromFile”
RETURN m.lnReturn
ENDPROC***************************************
PROCEDURE GetHICONFromString(tcString, tnXCoord, tnYCoord, tcFontName, ;
tnFontSize,
tnFontStyle, tnUnitofMeasure, ;
tnRGB,
tnAlpha, tnStringFormat)
***************************************
LOCAL logpColor, logpSolidBrush, logpFont, ;
logpStringFormat, logpPoint, logpGraphics,
;
logpBitamp, lnBitmap, lnIconHandle
DECLARE LONG GdipCreateHICONFromBitmap IN GDIPLUS INTEGER nBitmap, INTEGER @hbmReturn
DECLARE LONG GdipSetTextRenderingHint IN GDIPLUS LONG graphics, LONG mode
DECLARE LONG GdipSetInterpolationMode IN GDIPLUS LONG graphics, LONG interpolation
DECLARE LONG GdipSetSmoothingMode IN GDIPLUS LONG graphics, LONG SmoothingMdIF TYPE(“m.tcString”) = “C” AND TYPE(“m.tnXCoord”) = “N” ;
AND TYPE(“m.tnYCoord”) = “N” AND TYPE(“m.tcFontName”) = “C” ;
AND TYPE(“m.tnFontSize”) = “N”
SET CLASSLIB TO (ADDBS(HOME(1)) + “FFC\_gdiplus.vcx”)
*!* If the
last 4 params weren‘t
sent in, then give them default values
IF TYPE(“m.tnFontStyle”)
!= “N”
m.tnFontStyle = 0
ENDIF
IF TYPE(“m.tnUnitofMeasure”)
!= “N”
m.tnUnitofMeasure = 3
ENDIF
IF TYPE(“m.tnRGB”)
!= “N”
m.tnRGB = 0
ENDIF
IF TYPE(“m.tnAlpha”)
!= “N”
m.tnAlpha = 255
ENDIF
IF TYPE(“m.tnStringFormat”)
!= “N”
m.tnStringFormat = 0
ENDIFm.logpColor = CREATEOBJECT(“gpcolor”, MOD(m.tnRGB,
256), ;
MOD(BITRSHIFT(m.tnRGB,
8), 256), ;
MOD(BITRSHIFT(m.tnRGB,
16), 256), ;
m.tnAlpha)
m.logpSolidBrush = CREATEOBJECT(“gpsolidbrush”,
m.logpColor.argb)
m.logpFont = CREATEOBJECT(“gpfont”,
m.tcFontName, m.tnFontSize, m.tnFontStyle, m.tnUnitofMeasure)
m.logpStringFormat = CREATEOBJECT(“gpstringformat”,
m.tnStringFormat)
m.logpPoint = CREATEOBJECT(“gppoint”,
m.tnXCoord, m.tnYCoord)
m.logpbitmap = CREATEOBJECT(“gpBitmap”)
*!* Could
use GdipMeasureString to get the
*!* measurements
so that the size wasn‘t
*!* hardcoded
here
m.logpbitmap.CREATE(110, 24)
m.logpGraphics = CREATEOBJECT(“gpgraphics”)
m.logpGraphics.CreateFromImage(m.logpbitmap)
*!* The
following 3 lines of code make the
*!* rendered
text look nice – not all
jagged
GdipSetTextRenderingHint(m.logpGraphics.gethandle(),
3)
GdipSetInterpolationMode(m.logpGraphics.gethandle(),
7)
GdipSetSmoothingMode(m.logpGraphics.gethandle(),
4)
m.logpGraphics.DrawStringA(m.tcString,
m.logpFont, m.logpPoint, m.logpStringFormat, m.logpSolidBrush)
m.lnIconHandle = 0
GdipCreateHICONFromBitmap(m.logpbitmap.GetHandle(),
@m.lnIconHandle)
m.lnReturn = m.lnIconHandle
STORE .NULL. TO m.logpbitmap,
m.logpColor, m.logpSolidBrush, m.logpFont, m.logpStringFormat, m.logpPoint, m.logpGraphics
RELEASE m.logpbitmap, m.logpColor,
m.logpSolidBrush, m.logpFont, m.logpStringFormat, m.logpPoint, m.logpGraphics
ENDIF
CLEAR DLLS “GdipCreateHICONFromBitmap”, “GdipSetTextRenderingHint”,
;
“GdipSetInterpolationMode”, “GdipSetSmoothingMode”
RETURN m.lnReturn
ENDFUNC
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Visual FoxPro’s Future
What does the future hold for VFP?
This is perhaps one of the most asked questions lately. Most of the time when I’m
asked this question it is in regards to SednaX,
but today I’d like to talk about the contract work I recently started on Sedna.
The Microsoft Visual FoxPro Team is allowing me to talk about things that would ordinarily
be kept behind closed doors. In fact, when I asked them what I was allowed to talk
about, their response was pretty surprising. Basically they feel that the more that
we discuss, preview, and show before the eventual release of Sedna, the better (they
obviously weren’t just blowing smoke when they began touting the concept of transparency
– I must admit that before this I had my doubts).Windows Vista
The bulk of my work is being done on what some would call a Vista toolkit, but really
it’s just the Visual FoxPro Team and I working on some really cool and useful stuff
for Visual FoxPro using new features and APIs that are being unveiled by Microsoft
as they move towards Windows Vista. As Microsoft is back porting a lot of this new
stuff, some of these proposed Sedna components would work on Windows XP and maybe
even Windows 2000 as well. In the coming months you can expect to see lots of things
both here on my blog and also in the CTPs that will be released for Sedna. Most are
things that have never been done, or were never possible before, in Visual FoxPro.
Not excited now? You will be… OH, you will be! 🙂Let’s take a look at a few things that I’ve worked on that are being considered for
possible inclusion in Sedna…Windows Presentation Foundation (WPF) – XAML (codename was Avalon)
Below is a screen shot of XAML controls running inside a Visual FoxPro form.
When the buttons are clicked they actually fire Visual FoxPro methods. While this
example is just showing some simple drop-shadowed buttons, pretty much anything that
WPF is capable of doing with XAML could be done. So if you wanted something more complex,
like a 3D model that would spin around, you could have it. Think of a database application
for products where the user could rotate an image of the product a full 360 degrees.
XML Paper Specification (XPS)
Sometimes referred to as the Office 12 document format, XPS is going to be huge in
the coming years in my opinion. Given the open nature of the XPS format (basically
a bunch of XML documents inside a zip file), there will be a lot of 3rd party products
that will be coming out supporting XPS. So how about the ability to create XPS documents
from Visual FoxPro reports? Here’s a screen shot of one of the solution sample reports
in XPS format. It is being shown in the XPS viewer that Microsoft has created
for IE 7, but Microsoft will also be providing a standalone viewer as well. In XPS
format, the report’s text is fully searchable and the document can even be digitally
signed. Also, the rendered quality of an XPS document is super crisp and clear.
Task Dialogs
Say goodbye to the simple and somewhat tired looking Windows message box and
hello to Task Dialogs! Task dialogs are message boxes on steroids, and just one of
the new common controls provided by Microsoft in Windows Vista. What the screen shot
below doesn’t show is some of the other features that come with task dialogs, such
as enhanced button types, progressbars, additional icons, callback functions, additional
control areas… the list goes on and on. In addition to being very useful, task dialogs
can help give a Visual FoxPro application one of those little touches that makes it
look and feel more professional.
Speech API (SAPI)
Sorry, no screen shot for this one, but SAPI has really been improved in Windows Vista.
Imagine users using Visual FoxPro applications to do dictation (saved directly into
a memo file as data), or run queries… “Bring up customer, last name Smith”, “Show
me the February sales report”, “Upload progress report to headquarters”. Sounds a
bit futuristic perhaps, but given the new Speech engine in Windows Vista, all of this
and more is possible. I haven’t worked out what all the uses might be for this in
Visual FoxPro applications, but talking into a microphone and seeing the sentences
appear in an editbox on a Visual FoxPro form is still pretty neat. And, when thought
of in conjunction with the growing popularity of internet telephony (VoIP),
I have to think there is some use for speech recognition in the Visual FoxPro applications
of the future.More to come
That’s all for this blog entry, but certainly not all that is being worked on. I’ll
be back with more later. I just thought that some of you would enjoy seeing these,
and maybe it would generate some excitement and useful discussion here or out on the
Visual FoxPro forums. As for SednaX…
more is on the way there too. I promise.
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Visual FoxPro Visibility
Increased visibility
Visual FoxPro has gone from utter obscurity two years ago to showing up all over the
place these days. Visual FoxPro has been a meteor on the TIOBE
Index first showing up in the top 20 some three months ago and now eclipsing the
likes of VB.NET, Pascal, and COBOL. Mary Jo Foley has taken recent notice and posted repeated
news articles and blog entries about Visual FoxPro and the VFP Community (that
she endearingly refers to as the FoxPro Faithful). ENT News has taken
note in a few articles. And, RemondMag.com has
FoxPro popping corks. Presumably these corks are on champaign, but with
Visual FoxPro’s recent increase in visibility there may be some who weren’t expecting
(or wanting) this popping corks of another kind.Inevitable
Now some may find this increased exposure all very surprising. I mean, who knew that
Visual FoxPro existed or that it was even a Microsoft product? But to me, all of this
was inevitable. Visual FoxPro serves the customer base that Microsoft has neglected
to provide for in their other offerings, namely Visual Studio. Developer shops
not doing large team development projects and customers that are looking for super-fast,
robust, data-centric applications that won’t break the bank. Can Visual Studio create
applications that handle data? Sure, but it doesn’t hold a candle to what Visual FoxPro
can do and LINQ isn’t going to shore up the difference. Can Visual Studio be used
by a small development team on a small to medium-sized project? Sure, but that’s not
the target Microsoft has shot for with Visual Studio.What about .NET?
.NET is an incredible framework of thousands of classes that can help developers produce
modern looking, feature rich Windows applications. Well then, I guess Visual FoxPro
is doomed since it’s not a .NET language, right? Quite the contrary actually.
As a non-.NET language Visual FoxPro gets to continue creating data-centric applications
with blinding speed and flexibility, and at the same time it can leverage
the .NET framework where and when appropriate through the use of .NET assemblies and
COM Interop. I’ve already shown many examples on this blog of .NET controls and code
being run from Visual FoxPro. You can even compile and execute C# or VB.NET code from
Visual FoxPro using .NET’s CodeDom if you want to. What I’m saying is that .NET is
just a big beautiful framework of classes and it can be leveraged from a whole host
of languages… Visual FoxPro included. Visual Studio isn’t the only development tool
out there that can produce .NET assemblies or utilize the .NET framework… that was
the whole point of .NET – to be language independent.Visual FoxPro knows data
Visual FoxPro is probably one of the most misunderstood languages/development tools on
the planet. Most people think that Visual FoxPro is just a database that uses flat
files (DBF) for storage. While Visual FoxPro does provide developers with a time-tested,
feature-rich, database they can use, Visual FoxPro’s real power is in creating
database applications that access and modify data regardless of the backend. That
data can be in a Visual FoxPro database or in SQL Server, MySQL, Postgres, Oracle,
XML files, Access… whatever. Visual FoxPro knows data and knows how to work with
it regardless of the source. Feature rich Windows front-ends (screens and reports) for
any of these data sources can be created better and faster with Visual FoxPro than
with any other development platform in the world. What? That can’t be true can it?
Yes, it is true, that’s not an overstatement and I didn’t mispeak. Data-centric Windows
applications accessing any of the aforementioned backends can be created better
and faster with Visual FoxPro than with ANY other development platform in the
world.A few other things you might not know about Visual FoxPro…
- it’s object-oriented (one of the first OOP languages Microsoft had for that matter)
-
its built-in feature-rich database is royalty free (no per seat license fees
anyone?) -
is rabidly supported by a large community of developers (many of which have decades
of experience developing FoxPro applications – how many years of experience do the
developers on your project have in the tool they’re using?) -
not originally a Microsoft product (MS purchased it because it was better than anything
they had) -
it comes with a built in reporting engine (no 3rd party product needed –
who would have thought that reports would be important to data-centric applications?) -
you can purchase it today for about $550 from all kinds of places (like here,
or here,
or even here) - it’s got a really cool logo
What’s next for FoxPro?
Taking over the world. Either get on board or get out of the way.
UPDATE: 03-12-2006 Thanks to Alex Feldstein for pointing out Visual C++. Visual C++
1.0 was released in 1993 while Visual FoxPro 3.0 was released in 1995.
Subsequently corrected blog entry regarding Visual FoxPro being first Microsoft object-oriented
language.
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Visual FoxPro Progress
SednaX
In addition to the administrative duties that I share with Rick and Doug, I’ve been
working with Bo Durban on the GDIPlusX library. The GDIPlusX library is a pure Visual
FoxPro reproduction of the Drawing related namespaces in .NET. We’ve coded well over
40,000 lines of VFP code and the library consists of 80+ classes now. At nearly 90%
complete it is safe to say that no other library on the planet gives Visual FoPro
developers the fuctionality and power that this one does when working with GDI+. Cesar
Chalom posted a
recent example using the new library to create a gradient background for a form
(the new code is toward the bottom of the page – compare it with the old way of doing
things and I’m sure you’ll begin to see one of the benefits of GDIPlusX). To download
the GDIPlusX library as well as other useful VFP enhancements that are being worked
on go to SednaX and enter the Downloads
Section. For those of you that want to help, get involved! SednaX is open to everyone
in the VFP Community.The number of active projects and members (nearly 800 now) out on SednaX continues
to grow. We (Doug, Rick and I) are also receiving new project proposals on a near
weekly basis. Given that SednaX is still much less than a year old, I’d say we’re
right on track to take over the world.Vista Toolkit for VFP
I also continue to work with Microsoft on the portion of Sedna that
will help Visual FoxPro developers utilize some of the new technologies that Microsoft
is coming out with. There was a substantial amount of R&D prior to actually starting
on the actual products that will constitute the Vista Toolkit, but I am now working
on the real deal as they say. It’s been a pleasure to work with the Fox Team, especially
Milind Lele. He only cracks the whip every so often and has been receptive to input
and new ideas. That’s not to say he as gone for every world domination scheme I’ve
come up with, but he appears to have our (VFP Community’s) best interests at heart.A couple of pieces that you can look forward to seeing in the future are for Windows
Desktop Search (WDS) and the RSS Platform (msfeeds). Wrapper classes have been
created for both.Windows Desktop Search
For Windows
Desktop Search (WDS) I wrote an assembly in C# that allows VFP developers
to do WDS queries and return a recordset object. This is then turned into a Visual
FoxPro cursor via XML. Searches with WDS are lightning fast which makes it a perfect
fit for Visual FoxPro which is lightning fast when it comes to data. Here’s a screen
shot of a form I created that is using this new Vista Toolkit stuff.
RSS Platform
To handle the new RSS
Platform I created a set of VFP wrapper classes that can be used to consume RSS
feeds (including ATOM). I almost had to create a C++ DLL in order to handle the event
interfaces in msfeeds, but thanks to a recent
blog post by Calvin Hsia, I’ve been able to implement all of the wrappers in pure
VFP. I’ve found that if you ever need to do something truly insane in Visual FoxPro
that Calvin is the Go-To-Guy.MSFeeds comes with IE7 so with that in hand Visual FoxPro developers will be ready
to harness the power of RSS. Here’s a screen shot of an RSS reader I am creating in
pure Visual FoxPro that uses the new wrapper classes. Using the new wrapper classes
this sort of thing is almost too easy.
Less Blogging, More Work
So, while you may not have seen the usual amount of high activity on this blog lately,
rest assured that I am working hard to help the Visual FoxPro Community invent the
future of Visual FoxPro. Progress in many areas has been made and will continue to
be made. Of that much, I am sure. Next up? Renaming
SednaX and moving it over to CodePlex!
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