Thanks for your reply. However your sample code still not meet my requirement.
Here i want. If user input __1 then invoking the lostfocus event then the binding source will be set to 001 right? However the UI doesn't update at all it still dispaly __1. When i use common textbox control it works fine.
sender, RoutedEventArgs e)
Besides the code above works fine no matter i use myown base class or Telerik's ViewModelBase, it doesn't work only if you input the number inside the control. Pls have a try.
Please help me there.