Occurs when one or more System.Web.UI.WebControls.Parameter objects contained by the collection changes state.
If the System.Web.UI.WebControls.ParameterCollection collection is contained by a data source control, the ParameterCollection.ParametersChanged event raises the data source control's DataSourceChanged event, causing any data-bound controls to rebind.
Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.
The Parameter.OnParameterChanged 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.