My WPF application consists of a main window with a tab control which has a series of tab items, each hosting a user control.
I'd like one of the user controls to be able to trigger the application to change focus from the current tab to a different one.
Is there a way for the user control to trigger its tab control container to change to another tab item?
The WPF system provides the RoutedEvent. This special kind of event can be created to be catched by every element in the tree. With this way you can fire the event inside your user control, and catch it in the TabControl that will do everything you need. The tab control can catch the event cause of it lies in the element's tree of your window.
You can start from here: http://msdn.microsoft.com/en-us/library/ms742806.aspx
You'll need a Bubble Event.
Hope this helps.