Selects blocking mode.

A Boolean value.  

object.Blocking [= value]

The Blocking Property syntax has these parts:

If this property is set to True, none of the methods will return to your code until the command completes. In other words, the command will be handled synchronously.

If this property is False, all commands are handled asynchronously. They return to you immediately and you are notified of completion with the Done event. When the user-interface requires that the user is able to continue working while the control does its work, it is recommended that Blocking is set to False so that your program can respond quickly to user actions.