Signals the state of the control has changed.
IPostBackDataHandler.RaisePostDataChangedEvent
The MsgBox control calls the ReturnValueChanged event, if it has been set in the webform containing the control.
The event is called with the source object set to this MsgBox control, and an MsgBox.MsgBoxReturnArgs object.
MsgBox Class | BWare.UI.Web.WebControls Namespace