public class RowNumberColumn : GridViewDataColumn    {        public override System.Windows.FrameworkElement CreateCellElement(Telerik.Windows.Controls.GridView.GridViewCell cell, object dataItem)        {            TextBlock textBlock = cell.Content as TextBlock;            if (textBlock == null)            {                textBlock = new TextBlock();            }            //textBlock.Text = (this.DataControl.Items.IndexOf(dataItem) + 1).ToString();             textBlock.Text = ((this.DataControl.ItemsSource as IList).IndexOf(dataItem) + 1).ToString();            return textBlock;        }    }

<telerik:RadGridView>    <telerik:RadGridView.Columns>        <local:RowNumberColumn Width="32" Header="序号"/>     </telerik:RadGridView.Columns></telerik:RadGridView>