Question

I find myself needing to preform the same actions on both HtmlControls and WebControls. I am a firm believer in DRY and find the fact that there is only the Control class to use if I want to consolidate the functions on both types. The problem that I have with using Control is that there certain properties that both HtmlControl and WebControl expose that Control does not. In the current case, the Attributes property is the problem. Does anyone have any suggestions on how to avoid the duplication of code in this type of instance?

Answer 1

In the past I’ve duplicated code to set the attributes for HtmlControls and WebControls. However, here’s another idea:

Private Sub SetAttribute(ByRef ctrl As Control, ByVal key As String, ByVal value As String)
    If TypeOf ctrl Is HtmlControl Then
        DirectCast(ctrl, HtmlControl).Attributes(key) = value 
    ElseIf TypeOf ctrl Is WebControl Then
        DirectCast(ctrl, WebControl).Attributes(key) = value 
    End If
End Sub

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    For Each ctrl In Me.Controls
        SetAttribute(ctrl, "class", "classname")
    Next
End Sub