I have a dialog that pops up over the main screen (it\'s actually a user control that appears on the page as per the application demo from Billy Hollis) in my application that h
Have a look at the Binding.UpdateSourceTrigger property.
You can set the Binding
in your dialog like so
And then call the UpdateSource method in your button save event
myTextBox.GetBindingExpression(TextBox.TextProperty).UpdateSource();
Once you've called UpdateSource
the source object will be updated with the value from the TextBox