Creating Web User Controls

Creating a Web user control is not difficult; just select the File|New|Project and choose the Web Control Library item, or select the Project|Add Web User Control menu item.

For example, we created a new Web user control in the WebUserControls example on the CD-ROM, as discussed in the In Depth section of this chapter. The Web user control we created supports a DisplayColor property, a SetText method, and a TextModified event; here's the code in the WebUserControl1.ascx.vb file in that project that supports the new control:

Public MustInherit Class WebUserControl1
    Inherits System.Web.UI.UserControl
    Protected WithEvents Label1 As System.Web.UI.WebControls.Label

' Web Form Designer Generated Code...
    Private LabelColor As Color
    Public Event TextModified(ByVal NewText As String)

    Private Sub Page_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
    End Sub

    Property DisplayColor() As Color
        Get
            Return LabelColor
        End Get

        Set(ByVal Value As Color)
            LabelColor = Value
            Label1.BackColor = LabelColor
        End Set
    End Property

    Public Sub SetText(ByVal NewText As String)
        Label1.Text = NewText
        RaiseEvent TextModified(NewText)
    End Sub
End Class

For the details on this example, see the In Depth section of this chapter, as well as the next few topics.