protected void ToExcel(GridView gv,string name) {

            Response.Clear();

            Response.Buffer = true;

            Response.Charset = "GB2312";

            Response.AppendHeader("Content-Disposition", "attachment;filename=" + name + ".xls");

            // 如果设置为 GetEncoding("GB2312");导出的文件将会出现乱码!!!

            Response.ContentEncoding = System.Text.Encoding.UTF7;

            Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。

            System.IO.StringWriter oStringWriter = new System.IO.StringWriter();

            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);

            gv.RenderControl(oHtmlTextWriter);

            Response.Output.Write(oStringWriter.ToString());

            Response.Flush();

            Response.End();

        }

        public override void VerifyRenderingInServerForm(Control control)

        {

        }

        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

        {

            if (e.Row.RowType == DataControlRowType.DataRow)

            {

                e.Row.Cells[1].Attributes.Add("style", "vnd.ms-excel.numberformat:@;");

            }

        }

        protected void btnToExcel_Click(object sender, EventArgs e)

        {

            if (gvStat.Rows.Count > 0 && gvStat.Visible == true) {

                ToExcel(gvStat, "from " + ViewState["StartDate"].ToString() + " to " + ViewState["EndDate"].ToString());

            }

            else if (gvUser.Rows.Count > 0 && gvUser.Visible == true) {

                ToExcel(gvUser, "from " + ViewState["StartDate"].ToString() + " to " + ViewState["EndDate"].ToString());

            }

        }