Raises the SelectedIndexChanging event.
Assembly: System.Web (in System.Web.dll)
The SelectedIndexChanging event is raised when a row's Select button is clicked, but before the GridView control handles the select operation. This enables you to provide an event-handling method that performs a custom routine, such as canceling the selection operation, whenever this event occurs.
Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.
The method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.Notes to Inheritors
When overriding in a derived class, be sure to call the base class's method so that registered delegates receive the event.