Here are 2 generic classes (DataContextProxy and DataContextProxyBehavior) that help to pass data context from one control to resource so that other visual/or not visual can bind to.
DataContextProxy: Just a simple VM that hold DataContext object.
DataContextProxyBehavior: Simple behavior that can be attached to any FrameworkElement. Once attached, it tracks that FrameworkElement's DataContext. Any change of DataContext, it will pass the change to DataContextProxy. The goal is to have DataContextProxy be in resource that other visual/non visual can bind to.
Usage: See an example of declaration and usage at the bottom.
Hope it helps someone :)
01.publicclassDataContextProxy : SomeImplementationOfINotifyPropertyChanged02.{03. #region private data04. privateobject_dataContext;05. #endregion06. 07. #region public properties08. publicobjectDataContext09. {10. get{ return_dataContext; } 11. set{ _dataContext = value; FirePropertyChanged(() => DataContext); }12. }13. #endregion14. 15. #region constructors16. publicDataContextProxy()17. {18. _dataContext = null;19. }20. #endregion21.}
01.publicclassDataContextProxyBehavior : Behavior<FrameworkElement>02.{03. #region DataContextProxy Dependency04. publicDataContextProxy DataContextProxy05. {06. get{ return(DataContextProxy)GetValue(DataContextProxyProperty); }07. set{ SetValue(DataContextProxyProperty, value); }08. }09. 10. publicstaticreadonlyDependencyProperty DataContextProxyProperty =11. DependencyProperty.Register("DataContextProxy", typeof(DataContextProxy), typeof(DataContextProxyBehavior));12. #endregion13. 14. #region overrides15. protectedoverridevoidOnAttached()16. {17. base.OnAttached();18. 19. UpdateDataContext();20. AssociatedObject.DataContextChanged += AssociatedObjectOnDataContextChanged;21. }22. 23. protectedoverridevoidOnDetaching()24. {25. base.OnDetaching();26. AssociatedObject.DataContextChanged -= AssociatedObjectOnDataContextChanged;27. }28. #endregion29. 30. #region private functions31. privatevoidAssociatedObjectOnDataContextChanged(objectsender, DependencyPropertyChangedEventArgs args)32. {33. UpdateDataContext();34. }35. 36. privatevoidUpdateDataContext()37. {38. if(AssociatedObject != null&& DataContextProxy != null)39. {40. DataContextProxy.DataContext = AssociatedObject.DataContext;41. }42. }43. #endregion44.}
Sample Usage of DataContextProxy and DataContextProxyBehavior classes:
Create an instance of DataContextProxy in resource dictionary<UserControl.Resources> <DataContextProxyx:Key="DataContextProxy"/></UserControl.Resources>Use DataContextProxyBehavior to pass an element framework's DataContext to DataContextProxy<GridDataContext="{Binding SomeViewModel}"> <i:Interaction.Behaviors> <DataContextProxyBehaviorDataContextProxy="{StaticResource DataContextProxy}"/> </i:Interaction.Behaviors></Grid>In a non-visual or visual element, bind to DataContextProxy using StaticResource.<telerik:GridViewDataColumn.Header> <TextBlockText="{Binding DataContext.SomeTextPropertyOnSomeViewModel, Source={StaticResource DataContextProxy}}"/></telerik:GridViewDataColumn.Header>