' Override the OnLoad method to check if the 
' page that uses this control has posted back.
' If so, check whether this controls contains
' only literal content, and if it does,
' it gets the UniqueID property and writes it
' to the page. Otherwise, it writes a message
' that the control contains more than literal content.
Overrides Protected Sub OnLoad(ByVal e As EventArgs)

   If Page.IsPostBack = True Then
      Dim s As String

      If Me.IsLiteralContent() = True Then
         s = Controls(0).UniqueID
         Context.Response.Write(s)
      Else
         Context.Response.Write( _
         "The control contains more than literal content.")
      End If
   End If
End Sub