Adding a C# page to a VB.Net website

[Paul]

I have a website that is all written in VB.Net, but I would now like to add
a page with C# codebehind. If I just write it, it does not seem to work (I
added a label control then had the text property set in the codebehind to a
string. I get no error, and am pretty sure it is okay, but the codebehind
does not seem to "take" (the label says label, as the default in the aspx
page.(There is also other code that does not fire, but works fine in a
separate website all written in C#. Is there anything I need to do to the
C# page or the Website?

TIA