Call this member function to set the active view.
Specifies a pointer to a CView object, or NULL for no active view.
Specifies whether the view is to be notified of activation. If TRUE, OnActivateView is called for the new view; if FALSE, it is not.
The framework will call this function automatically as the user changes the focus to a view within the frame window. You can explicitly call SetActiveView to change the focus to the specified view.