datagrid截取字符串

datagrid怎么截取标题只显示8个字，后面用“...”代替
我的前台代码  
<asp:DataGrid ID="DataGrid2" runat="server" AutoGenerateColumns="False"
                                        BorderStyle="None" BorderWidth="0px" CellPadding="0" ShowHeader="False">
                                         <Column>
                                            <asp:HyperLinkColumn Text="&lt;img src=image/dir_pointer_g.gif border=0&gt;"></asp:HyperLinkColumn>
                                          
                                            <asp:HyperLinkColumn Target="main" DataNavigateUrlField="mid" DataNavigateUrlFormatString="login.aspx?id={0}" DataTextField= '<%# FormatStringl(DataBinder.Eval(Container.DataItem,"url").ToString())%>' >
                                                    <HeaderStyle HorizontalAlign="Center" Width="220px"></HeaderStyle>
                                                   
                                                </asp:HyperLinkColumn>
                                        <Column>
</asp:DataGrid>

如何显示在HyperLinkColumn中啊？高手帮忙！！