In last week’s column,
we introduced Visual Studio 2005’s new code snippet features. The built-in
snippets are great, but Visual Studio 2005 takes it a step further by allowing
you to create your own for reuse in a project or projects. This week, we extend
the concept by creating custom code snippets to easily reuse common code blocks
in your application.

Creating the file

Code snippets are defined in XML files with the .snippet
file extension. Microsoft created the Code Snippet XML
Schema, which defines the structure of a snippet XML file and specifies the
elements (and their attributes) that you may use in a code snippet file.

Since code snippets are defined as XML, you can use your
favorite XML or text editor to create and maintain them. Visual Studio 2005 supports
XML editing, so it may be used to remain in a common environment.

Snippet example

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Depending on the project or organization, many code snippet
candidates may exist. This may be a discrete chunk of code that you may reuse
throughout the code (this also lends itself to a code library). In addition,
the code may or may not include replaceable parameters that allow you to
enforce a coding technique.

For demonstration, I will create a code snippet that
declares a set of objects for working with SQL Server. This allows a developer
to insert and use these objects while saving typing time. Here is the C# code
snippet:

SqlConnection conn;

SqlCommand comm;

SqlDataAdapter sda;

Listing A
contains the appropriate code snippet XML.
Listing B contains the equivalent code snippet definition for VB.NET. Here’s a closer look at the XML:

  • A
    code snippet is defined by the CodeSnippet element. The CodeSnippets
    element is the root node, and it may contain one or more CodeSnippet
    elements.
  • The
    Description, Author, and Shortcut elements appear in the Code Snippets
    Manager window when it is highlighted. For this reason, the text included
    in the Description element should give a good idea of what the snippet
    actually does. In addition, the Shortcut element is what is typed within
    Visual Studio 2005 to actually use the snippet (type the shortcut and hit
    [Tab]).
  • The
    Code element contains the actual code associated with the snippet. In this
    example, there are no replaceable parameters used. The code is placed
    within the CDATA attribute.
  • The
    Language attribute of the Code element defines the code used. The options
    include VB, CSharp, VJSharp, and XML.

You should create a folder to contain your custom code
snippets and save this sample in the folder. The next step is to make it available in Visual Studio 2005.

Adding a snippet to Visual Studio 2005

The Code Snippets Manager allows you to easily add your own
code snippets to the environment. To do so, you should follow these steps:

  1. Open
    the Manager window via the Tools | Code Snippets Manager menu selection.
  2. Select
    the appropriate language in the Language field.
  3. Click
    the Add button to add your snippet to the environment. This opens the Code
    Snippets Directory window that allows you to navigate to the folder
    containing the snippet file(s). You don’t select the actual snippet
    file—the folder is selected and all snippets within it are added.
  4. Once
    the directory is added, you can select it and browse the files within it.

You can test it by typing the appropriate shortcut in Visual
Studio 2005 and hitting [Tab] to insert the code, or you can right-click and select
Insert Snippet from the context menu. This allows you to navigate the available
code snippet directories to locate one if you don’t know its shortcut. If
you’re using C#, you may also use the Surround With context menu option. This
is just one way to tackle this simple example.

More examples

The Code Snippet XML Schema includes the optional
Declarations element that you may use to specify the literals and objects for
the code specified in the snippet. It might include zero or more Literal
elements that you may use to define literals, and zero or more Object elements
to define objects used in the code. Literal and Object elements contain ID,
ToolTip, and Default elements to assign a name to the item, tooltip text, and
its default value. In addition, the Object element contains the Type element to
specify the type of object.

The Object and Literal elements are used in the actual code
within the Code element. You reference the literals and objects you declared in
the Declarations element by placing $ symbols at the beginning and end of the
value in the literal or object’s ID element. The VB snippet file in Listing C uses these elements to
declare literals to be used in our code.

When you use this code snippet, green boxes appear around
the literals enclosed in dollar signs ($connString$ and $sqlString$), which
allow you to insert the appropriate text. The example code snippets in this
column provide a peek at the creation process, but there is much more functionality
available via the Code Snippet XML Schema.

Importing code snippets

While creating custom code snippets provides power and
flexibility, you may also import snippets (created by you or others) to Visual
Studio 2005. This is available via the Import button in the Code Snippets Manager.
This allows you to bring snippets into existing directories used by the Code
Snippets Manager. You select the destination directories and select the Finish
button. The process physically copies the snippet file to the destination
directory. Microsoft provides plenty of Visual Studio 2005 code snippets,
which you can download and import into your environment.

Third-party tools

It can be a bit tedious to create and edit XML files. It is
especially cumbersome when you must know the syntax and order of a valid
element that you may use in the snippet file. While Visual Studio 2005 does not
include a snippet editor, there are code snippet editor tools available:

Customize your environment

Creating custom code snippets allows you to customize and
streamline your development environment by making it easy to reuse standard
coding elements and save typing. Use your favorite XML or text editor to create
your own snippets and add them to Visual Studio 2005 to save valuable time.

Tony Patton began his professional career as an application developer earning Java, VB, Lotus, and XML certifications to bolster his knowledge.

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