asp.net中Gridview导出Excel

前台：
<div>
        <asp:GridView ID="GridView1" runat="server" >
        </asp:GridView>
        <br />
        <asp:Button ID="btnExportToExcel" runat="server" 
            onclick="btnExportToExcel_Click" Text="导出数据到Excel" />
    </div>

后台：
/// <summary>
    /// 将GridView的数据输出到Excel文件
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void btnExportToExcel_Click(object sender, EventArgs e)
    {
        if (GridView1.Rows.Count == 0)
        {
            return;
        }
        Response.ClearContent();
        Response.ContentEncoding = Encoding.Default;
        Response.AddHeader("content-disposition", "attatchment;filename=" + HttpUtility.UrlEncode("我的Excel.xls", Encoding.UTF8));
        Response.ContentType = "application/ms-excel";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        GridView1.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();
    }

    //必须重载此方法，以便支持上面的导出操作
    public override void VerifyRenderingInServerForm(Control control)
    {

    }