Gradview绑定数据库数据并导出Excel

Code
protected void showData_Click(object sender, EventArgs e)
    {
        SqlConnection myConnection
         = new SqlConnection("Data Source=localhost;Initial Catalog=test;User ID=sa;password=sa");

        SqlDataAdapter ad = new SqlDataAdapter("SELECT * FROM booklist", myConnection);
        DataSet ds = new DataSet();
        ad.Fill(ds);
        this.gvShowData.DataSource = ds;
        this.gvShowData.DataBind();
    }

//导出Excel表
    protected void btnExportToExcel_Click(object sender, EventArgs e)
    {
        Response.Charset = "GB2312";
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        Response.AddHeader("Content-Type", "application/vnd.ms-excel");
        Response.AddHeader("Content-Disposition", "myexcelfile.xls");
        //以此编码模式导出才不会出现乱码
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        gvShowData.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();
    }

//一定要写，否则出错！！
    public override void VerifyRenderingInServerForm(Control control)
    {
    }