gridview导出到Excel 问题

 //这个主要是为了解决导出时候说什么必须放在runat="server" 里面。。这主要是为了解决这个错误
public override void VerifyRenderingInServerForm(Control control)
        {
            // Confirms that an HtmlForm control is rendered for
        }

        /// <summary>
        /// 数据绑定。。这个主要是解决数字类型出现错误。
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                for (int i = 0; i < e.Row.Cells.Count; i++)
                {
                    e.Row.Cells[i].Attributes.Add("style", "vnd.ms-excel.numberformat: @;");

                }
            }

        }