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        protected void btnExport_Click(object sender, EventArgs e)
        {
            DictHolidayReportType reportType = (DictHolidayReportType)Enum.Parse(typeof(DictHolidayReportType), ddlReportType.SelectedValue);
            Response.ClearContent();
            Response.Buffer = true;
            Response.Clear();
            Response.Charset = "UTF-8";
            Response.ContentEncoding = System.Text.Encoding.Default;
            Response.AddHeader("content-disposition", string.Format("attachment; filename=\"{0}\".xls", GetReportTypeFileName((byte)reportType)));
            Response.AddHeader("Content-Type", "application/vnd.ms-excel");

            StringWriter sw = new StringWriter();
            HtmlTextWriter htw = new HtmlTextWriter(sw);
            gvReports.AllowPaging = false;

            gvReports.HeaderRow.Style.Add("background-color", "#FFFFFF");
            gvReports.HeaderRow.Style.Add("text-align", "center");
            gvReports.HeaderRow.Cells[0].Visible = false;

            for (int i = 0; i < gvReports.HeaderRow.Cells.Count; i++)
            {
                gvReports.HeaderRow.Cells[i].Style.Add("background-color", "#ff3300");
            }
            foreach (GridViewRow row in gvReports.Rows)
            {
                row.Style.Add("text-align", "center");
                row.HorizontalAlign = HorizontalAlign.Center;
                row.Cells[0].Visible = false;
            }
            gvReports.RenderControl(htw);
            Response.Write(sw.ToString());
            Response.End();    
        }