Is it possible to create your own widgets in XAML?

Question

Is it possible to create your own widgets in XAML?

Answer 1

Yes, they are usually called custom controls. Controls can be used as a base class for your new control. Do mind that WPF favors composition over inheritance. You don't need to use inheritance (custom control) to make a listbox with checkboxes. The standard ListBox can do that just fine with composition. WPF controls should also be designed as look-less controls. The look of the control should be separate of the behavior. See http://msdn.microsoft.com/en-us/magazine/cc163421.aspx for an example.

Answer 2

There are multiple ways to create your own controls in WPF ranging from very simple customizations to full fledged controls like those included in WPF. This is all documented in the MSDN section for control customization.