Question

i wonder if it’s possible to define a variable/property of more than one type.

Let’s say i want a property TextWebControl that is a WebControl and also implements Web.UI.ITextControl(f.e. like a TextBox or Label). But i don’t want to enforce that it is a TextBox or Label, but only one that inherits from WebControl and also implements ITextControl so that it also would work with controls added in future releases of .Net-Framework.

• .Net-Framework 4.0

Edit: I have retagged the question and added VB.Net because it’s my default language. Normally it’s no problem for me to understand C# also, but i must admit that it’s difficult to translate generic stuff to VB.Net without experiences and it’s also better documentated in C# than in VB. So i would appreciate(and aceept) a working example of a VB.net generic type of ITextControl/WebControl.

From Marc’s answer i understand that i need a generic class. But how do i instantiate it in SomeClass? This won’t compile:

Class SomeClass
   Public Property info As InfoControl(Of WebControl, ITextControl)
End Class

Public Class InfoControl(Of T As {WebControl, ITextControl})
End Class

Thank you very much.

Answer 1

Only inside generics, i.e.

void SomeMethod<T>(T whatever) where T : WebControl, ITextControl {...}

Otherwise, you are going to have to pick between them, or have 2 variables.