how to make a base control in silverlight

Question

I have a user control in silverlight which contains both XMAL and .cs file.
But I wanna make it into a base control.
In other word,I can make a control inherited it whose area in it can be edited.
Just like Master Page in asp.net,you know.
In the base control,I only have a lot of description in XMAL,perhaps it can be described in the .cs file,too.

Answer 1

In fact I use this.DefaultStyleKey = typeof(CLASS NAME);
to load its default style which is written in the Generic.xaml .
I think it is the solution.