For internal use only. The DragStartValue property can be used to keep DateTime value, where end-user started to drag appointment. It might be any time between app.Start and End values. If you set this field at the beginning of the drag and drop operation, later you can determine appointment.Start value as LastAcceptedStart.Add(newStart.Subtract(DragStartValue)), where newStart is DateTime value under the pointer. Appointment.EndEdit and CancelEdit methods reset this field to DateTime.MinValue.

'宣言
 
Public Property DragStartValue As System.Date

public System.DateTime DragStartValue {get; set;}