Export dynamic table to excel file

public void ExportHtmlTabletoExcel()

        {


            try

            {

                Response.Clear();

                Response.Buffer = true;

                this.EnableViewState = false;

                string attachment = "attachment;   filename=yourPageName.xls";

                Response.AddHeader("content-disposition", attachment);

                Response.ContentType = "application/ms-excel";

                StringWriter sw = new StringWriter();

                HtmlTextWriter htw = new HtmlTextWriter(sw);

                HtmlForm frm = new HtmlForm();

                panReport.Parent.Controls.Add(frm);

                frm.Attributes["runat"] = "server";

                frm.Controls.Add(panReport);

                frm.RenderControl(htw);

                Response.Write(sw.ToString());

                Response.End();

            }

            catch (Exception ex)

            {

                throw ex;

            }
        }

         public override void VerifyRenderingInServerForm(Control control)

        {

            /* Verifies that the control is rendered */


        }

protected void imgbtnExcel_Click(object sender, ImageClickEventArgs e)

        {

            try

            {

                ExportHtmlTabletoExcel()

            }

            catch (Exception ex)

            {

                throw ex;

            }

        }

    }

public void fillgrid()
    {
        DataTable dt = new DataTable();
        dt = Employee.selectgrid();
        grdArea.DataSource = dt;
        grdArea.DataBind();
    }

 public void convertexcel()
    {
            try
            {
                Response.Clear();
                // ExportGridExel();
                GridView grdExcel = new GridView();
                grdExcel.AutoGenerateColumns = true;
                DataTable dtExcel = (DataTable)ViewState["viewRecordEX"];
                grdExcel.DataSource = (DataTable)ViewState["viewRecordEX"];
                grdExcel.DataBind();
                //Set the content type to Excel.
                grdExcel.AllowPaging = false;
                
                //Set the content type to Excel.
                Response.ContentType = "application/excel";   //ViewofEmployeeMaster.ms-excel
                Response.AddHeader("content-disposition", "attachment;filename=ViewofEmployeeMaster.xls");
                //Remove the charset from the Content-Type header.
                Response.Charset = "";
                //Turn off the view state.
                this.EnableViewState = false;
                System.IO.StringWriter tw = new System.IO.StringWriter();
                System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
                //code written for excel 
                HtmlForm frm = new HtmlForm();
                frm.Attributes.Add("ID", "frm");  // form1   //frm1
                frm.Attributes.Add("runat", "Server");


                GridViewRow row1 = new GridViewRow(0, -1, DataControlRowType.Header, DataControlRowState.Normal);
                TableCell rowheader1 = new TableHeaderCell();
                rowheader1.Text = "EMPLOYEE MASTER RECORDS";
               //rowheader1.BorderWidth = 0;
                rowheader1.ColumnSpan = 12;
                rowheader1.Font.Size = 20;
                rowheader1.HorizontalAlign = HorizontalAlign.Left;
                row1.Cells.Add(rowheader1);
                Table t1 = grdExcel.Controls[0] as Table;
                if (t1 != null)
                {
                    t1.Rows.AddAt(0, row1);
                }
                ////Add  Header Text
                //GridViewRow row = new GridViewRow(1, -1, DataControlRowType.Header, DataControlRowState.Normal);
                //TableCell totals = new TableCell();
                ////  totals.ColumnSpan = 18;
                //totals.Text = ViewState["empname"].ToString() + " - " + ddlSubQruery.SelectedItem.Text;
                //totals.BorderWidth = 0;
                //totals.HorizontalAlign = HorizontalAlign.Center;
                //totals.ColumnSpan = 8;
                //row.Cells.Add(totals);
                //Table t = gvViewRecordEmp.Controls[0] as Table;
                //if (t != null)
                //{
                //    t.Rows.AddAt(1, row);
                //}
                //Add Blank Row
                GridViewRow rowblk5 = new GridViewRow(0, -1, DataControlRowType.Header, DataControlRowState.Normal);
                TableCell tblblnk5 = new TableCell();  //TableHeaderCell()
                tblblnk5.BorderWidth = 0; 
                //tblblnk.ColumnSpan = 18;
                rowblk5.Cells.Add(tblblnk5);
                Table tblk5 = grdExcel.Controls[0] as Table;
                if (tblk5 != null)
                {
                    tblk5.Rows.AddAt(1, rowblk5);
                }
                //Add Blank Header
                //GridViewRow rowblk = new GridViewRow(2, -1, DataControlRowType.Header, DataControlRowState.Normal);
                //TableCell tblblnk = new TableHeaderCell();
                //tblblnk.BorderWidth = 0;
                //tblblnk.ColumnSpan = 18;
                //rowblk.Cells.Add(tblblnk);
                //Table tblk = grdArea.Controls[0] as Table;
                //if (tblk != null)
                //{
                //    tblk.Rows.AddAt(2, rowblk);
                //}
                frm.Controls.Add(grdExcel);
                // gvViewRecordEmp.Columns[6].Visible = false;
                //  gvViewRecordEmp.Columns[5].Visible = false;
                //end code
                //Get the HTML for the control.
                grdExcel.RenderControl(hw);
                //Write the HTML back to the browser.
                Response.Write(tw.ToString());
                //End the response.
                Response.End();
            }
            catch (Exception ex)
            {
                throw ex;

            }
        }