This time I found a thorny problem, for I'm a new.
When I binding an object to the page in WPF, and the object has a Property of XmlDocument Datatype. And I bind an element of the Property(XmlDoc ument) to a TextBox, when I change the TextBox's content, how I can trigger the Property' set and trigger the PropertyHasChan ged EventHandler.

Maybe, means this, when I just changed an element of an object's property that is a XmlDocument...