C# - How To Tell If The Control Or Control Interface Is Editable By The User

I'm looping through an array of controls and need to know which controls an end-user has the ability to (via JavaScript or directly) change the value that gets posted back. Where can I find such a list?

So far I have this:

Private Function IsEditableControl(ByVal control As Control) As Boolean
Return TypeOf control Is IEditableTextControl _
OrElse TypeOf control Is ICheckBoxControl _
OrElse GetType(ListControl).IsAssignableFrom(control.GetType()) _
OrElse GetType(HiddenField).IsAssignableFrom(control.GetType())
End Function