Occurs when the value of the DetailsView.PageIndex property changes before a paging operation.
The System.Web.UI.WebControls.DetailsView control raises the DetailsView.PageIndexChanging event when a pager button (a button with its CommandName property set to "Page") within the control is clicked, but before the System.Web.UI.WebControls.DetailsView control handles the paging operation. This allows you to provide an event handler that performs a custom routine, such as canceling the paging operation, whenever this event occurs.
This event is not raised when you programmatically set the DetailsView.PageIndex property.
Pager buttons are usually located in the pager row of a System.Web.UI.WebControls.DetailsView control.
A System.Web.UI.WebControls.DetailsViewPageEventArgs object is passed to the event handler, which allows you to determine the index of the page selected by the user and to indicate that the paging operation should be canceled. To determine the index of the page selected by the user, use the DetailsViewPageEventArgs.NewPageIndex property. To cancel the paging operation, set the System.ComponentModel.CancelEventArgs.Cancel property of the System.Web.UI.WebControls.DetailsViewPageEventArgs object to true.
For more information about handling events, see Consuming Events.