C# 4 and .NET 4

1188 ❘ ChaPTer 41 Asp.net feAtures
Club
This defines a default state for your control, which is a picture of a club along with a label. The ~ in the path
to the image means “start at the root directory of the web site.” Before you add functionality, you will test
this default by adding this control to a web page, so before continuing, add a new web page called Default
.aspx to the web site.
To use a custom control in an .aspx file, you first need to specify how you will refer to it, that is, the name
of the tag that will represent the control in your HTML. To do this, you use the directive
at the top of the code in Default.aspx, as follows:
code snippet PCSUserCWebApp1/Default.aspx
The TagPrefix and TagName attributes specify the tag name to use (in the form ),
and you use the Src attribute to point to the file containing your user control. Now you can use the control
by replacing the existing element in the file with code as follows adding the following element:
This is all you need to do to test your user control. Figure 41-1 shows the results of running this code.
figure 41-1
As it stands, this control groups two existing controls, an image and a label, in a table layout. Therefore, it
falls into the category of a composite control.
Adding a Suit Property
To gain control over the displayed suit, you can use an attribute on the element. Attributes
on user control elements are automatically mapped to properties on user controls, so all you have to do to
make this work is add a property to the code behind your control, PCSUserC1.ascx.cs. Call this property
Suit, and let it take any suit value. To make it easier for you to represent the state of the control, you define
an enumeration to hold the four suit names. The best way to do this is to add an App_Code directory to your
web site, and then add a .cs file called Suit.cs in this directory. App_Code is another “special” directory,
like App_Data, whose functionality is defined for you — in this case it holds additional code files for your
web site. You can add this directory by right-clicking the web site in Solution Explorer and clicking Add
ASP.NET Folder ➪ App_Code. When you have done this, add Suit.cs with code as follows:
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