Again I struck in a framework bug which doesn't allow us to declare and use a dependency property of Type Uri.ie If you declare a dependency property of type Uri and try to set from xaml , will throw an error at runtime.Here is scenario.
You are creating a custom control and you need to have a dependency of type Uri Named Source.
You declared as follows.
Fine.But If you create its instance in xaml as follows and run the application it will throw an error.
The error is AG_E_PARSER_BAD_PROPERTY_VALUE.
Microsoft has identified this error and rectified.Details here
Until the next version change the property type into string and use converters in xaml.
Or in the setter of a dummy property convert the value into Uri and keep in actual property.