.net gridview导出成excel汉字是乱码问题

.net gridview导出成excel,两个功能界面，代码是复制过来的，但是导出的excel一个汉字是乱码，一个正常，是哪里的问题呀？
代码如下，请指教
protected void btnExcel_Click(object sender, EventArgs e)
{
DateTime dt = System.DateTime.Now;
string str = dt.ToString("yyyyMMddhhmmss");
str = str + "-汇总.xls";

    selectFlag = 1;
    GridView2.AllowPaging = false;

    SelectGetData();
    GridViewToExcel(GridView2, "application/ms-excel", str);


}

/// <summary>
/// 将网格数据导出到Excel
/// </summary>
/// <param name="ctrl">网格名称(如GridView1)</param>
/// <param name="FileType">要导出的文件类型(Excel:application/ms-excel)</param>
/// <param name="FileName">要保存的文件名</param>
public static void GridViewToExcel(Control ctrl, string FileType, string FileName)
{
    HttpContext.Current.Response.Clear();
    HttpContext.Current.Response.Buffer = false;
    HttpContext.Current.Response.Charset = "UTF-8";
    HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8");//注意编码
    HttpContext.Current.Response.AppendHeader("Content-Disposition",
       "attachment;filename=" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8).ToString());
    //HttpContext.Current.Response.AddHeader(
    // "content-disposition", string.Format("attachment; filename={0}", FileName));                                     
    // HttpContext.Current.Response.ContentType = FileType;//image/JPEG;text/HTML;image/GIF;vnd.ms-excel/msword 
    HttpContext.Current.Response.ContentType = "application/ms-excel";
    HttpContext.Current.Response.Write("<meta http-equiv=Content-Type content=/text/html; charset=UTF-8/>");
    ctrl.Page.EnableViewState = false;
    StringWriter tw = new StringWriter();
    HtmlTextWriter hw = new HtmlTextWriter(tw);
    ctrl.RenderControl(hw);
    HttpContext.Current.Response.Write(tw.ToString());
    HttpContext.Current.Response.End();
}

public override void VerifyRenderingInServerForm(Control control)
{

}


protected void btncancel_Click(object sender, EventArgs e)
{
    Response.Redirect("content.aspx");
}