I'm trying to create a user control that I can use as a base for other user controls. So created this:

public abstract partial class _ViewBase : UserControl
{
    public _ViewBase()
    {
        InitializeComponent();
    }

    public abstract void Add();
    public abstract void Edit();
    public abstract void Remove();
    public abstract void Save();
}

The I get the comp error:

Partial declarations of 'UserView' must not specify different base classes

So I Googled it, found and followed this: http://geekswithblogs.net/lbugnion/archive/2007/03/02/107747.aspx

Now I get:

"_ViewBase" cannot be the root of a XAML file because it was defined using XAML. 

How in the world do you subclass a user control in WPF???