绑定SqlDataSource的Gridview字符串字段长度截取

绑定SqlDataSource的Gridview字符串字段长度截取
前台gridview中

加模版列
<asp:TemplateField HeaderText=" 内容 ">                                    
                                     <ItemStyle HorizontalAlign="Center" />
                                     <HeaderStyle HorizontalAlign="Center" Width="15%" />
                                     <ItemTemplate>
                                         <%# CutString(Convert.ToString(Eval("Content")), 20)%>
                                     </ItemTemplate>
                               </asp:TemplateField>

后台代码中
/// <summary>
         /// 字符长度控制 中文 英文识别！
         /// 注：一个汉字作为2个字符长度处理
         /// </summary>
         /// <param name="str">要进行切割的字符串</param>
         /// <param name="len">返回的长度（自动识别中英文）</param>
         /// <returns></returns>
         protected string CutString(string str, int len)
         {
             byte[] sarr = System.Text.Encoding.Default.GetBytes(str);

             if (sarr.Length > len)
                 return System.Text.Encoding.Default.GetString(sarr, 0, len) + "...";
             else
                 return str;
         }