This delegate specifies the parameter list that a method must have to handle the DataGrid.PageIndexChanged event. If you are using automatic paging (and have set the DataGrid.AllowPaging property to True, but the DataGrid.AllowCustomPaging property to False), your event handler only needs to set the new DataGrid.CurrentPageIndex.
public delegate void DataGridPageChangedEventHandler(object source, DataGridPageChangedEventArgs e);