Assembly: System.Web (in System.Web.dll)
The event is raised when a WebPart or other server control is being moved within its own zone, or to another zone. This can occur both when a user drags a control, and when there is a programmatic move.
The event is raised by the OnWebPartMoving method, and it provides an opportunity to cancel the moving process before it is complete. If the move is completed and the control placed in a new position, this event is followed by the WebPartMoved event.
Page developers can create a custom handler for the event by adding the OnWebPartMoving attribute to the <asp:webpartmanager> element, and assigning a custom method name to the attribute.