You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.  
The application uses the drag-and-drop functionality. 
You need to ensure that the drag-and-drop operation is stopped when a user moves the cursor outside the boundaries of the application form. 
Which enumeration member should you use?（）

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.  
The application uses the background worker process (BWP).  
When the user clicks a button,
the background worker executes a method named DoCalculations asynchronously. 
You need to implement a progress bar on the user interface (UI) that informs the user of the progress of DoCalculations. 
Which two actions should you perform?（）