jsFiddle is one of my favorite online tools, because it allows you to easily test and prototype JavaScript, HTML,
and CSS
within your browser. I had never dreamed of such a tool for .NET developers,
but .NET Fiddle brings the same features
to C# and VB.NET developers.

Basically, it allows you to fiddle around with
code snippets within a browser window negating the need to load Visual Studio, which is overkill when you just want to work with a small amount of code. One of .NET Fiddle’s biggest selling points is that it’s free.

Test code

The basic
.NET Fiddle interface is shown in Figure A. The left portion of the interface contains
options for Language (C#
or VB.NET), Project Type (Console or Interactive), NuGet
Packages, and whether Auto Run is enabled. Interactive mode allows you to type
lines of code without structure, while Console mode includes the Program class and
Main method. The Auto Run option allows you to determine if code typed via
Interactive mode executes as it is typed.

Figure A


The basic .NET Fiddle interface loaded for the first time.

The NuGet
Packages option allows you to use various packages within your code. You’re restricted to the packages made available by the .NET Fiddle team; the
list shown in
Figure B is displayed when the exclamation mark (adjacent to the NuGet Packages option) is selected. The .NET Fiddle team promises to continually update
this list, so check frequently for what is available.

Figure B


.NET Fiddle NuGet package options that are currently available.

The middle area of Figure A is the most important part of the tool — it’s where code is entered. The bottom middle window shows the output/results of running a code block (or errors) with code statistics in the lower right window.

Figure C
shows the results of executing C# code that deals with basic arrays. The output
of the Console statements is displayed in the output area of the window while
code statistics appear in the lower right. The statistics include when the code
executed; how long it took to compile and execute; memory consumed and CPU
execution time. The statistics are not overwhelming in this example, but they
can be useful when tracking or debugging code execution.

Figure C



Executing sample C# array code in .NET Fiddle.

A full-featured

I expected a
rudimentary editor with .NET Fiddle (basically, a text editor within the
browser), but it brings much more to the table. It provides code validation as
well as IntelliSense, which is a godsend since I don’t know anybody that
remembers syntax for the overwhelming number of objects and methods available.
In addition, it will validate code on the fly and offer a visual clue when
there are problems.

Figure D
shows IntelliSense and validation in action for sample Structs code.
IntelliSense offers valid methods and properties when the object name and
period is typed, while validation shows that the one line (SS.Y) includes an
invalid property name. I chose to use custom code to demonstrate that IntelliSense
works for custom as well as built-in .NET objects.

Figure D



.NET Fiddle code editor offers both Intellisense and validation.


While the
ability to test code within the browser is great, the collaboration features
available in .NET Fiddle are icing on the cake. Like its jsFiddle counterpart,
.NET Fiddle provides the ability to share code via URL, but it goes further by
providing real-time collaboration. Clicking the Collaborate button at the top
of the .NET Fiddle interface opens the window shown in Figure E.

.NET Fiddle uses TogetherJS to facilitate collaboration; Figure F shows the interface once collaboration is initialized (click it
again to close or stop collaboration). You can invite others to work on the
code or chat (via IM or audio) with the link provided (Figure F). You can share code the old-fashioned way via the
Share button (at the top of the interface), which allows you to let others view code via
URL or by embedding on a web page (Figure G).

Figure E



Collaborating with .NET Fiddle utilizes TogetherJS.

Figure F



initiated within .NET Fiddle.

Figure G



.NET Fiddle code sharing options.

A fun and
useful tool

Studio is a great tool for application development, but it’s overkill when
you just want to play around with code that may or may not result in a
full blown project. The .NET Fiddle project provides an impressive cross-browser interface; I tested it in the latest version of Chrome,
and Internet Explorer with no problems.

I often develop code solo, but the
collaboration options are full of opportunity. It will be interesting to see if
it’s used in discussion forums where code is often posted for analysis.

Have you used .NET Fiddle? If not, do you think you’ll give it a try? Let us know in the discussion.