virtual BOOL BeginDrag( CPoint pt );
Return Value
Nonzero if dragging is allowed, otherwise 0.
Parameters
pt
A CPoint object that contains the coordinates of the item being dragged.
Remarks
Called by the framework when an event occurs that could begin a drag operation, such as pressing the left mouse button. Override this function if you want to control what happens when a drag operation begins. The default implementation captures the mouse and stays in drag mode until the user clicks the left or right mouse button or presses ESC, at which time the drag operation is canceled.