How to insert value into excel column in C#?

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C#

I can create a new Excel sheet by using the Stored Procedure in the following code, but can't understand how to insert one value from an ASP.Net control into the last column of the Excel Sheet. I searched Google, but many articles use their own libraries files which cannot be downloaded. So how can I implement in this code only?

private void ExportFromSQL()
        {
            try
            {
                System.Data.DataTable dtexcel = new System.Data.DataTable();
                Hashtable ht = new Hashtable();

                dtexcel = BindComboWithParm(ht, "Get_Cols_Forexcelsheet");
                //dtexcel.Columns.Add("Company Id", typeof(string));

                //foreach (DataRow dr in dtexcel.Rows)
                //{
                //    dr["Company_Id"] = lblUploadRegistrationId.Text;
                //}
                using (XLWorkbook wb = new XLWorkbook())
                {

                    wb.Worksheets.Add(dtexcel, "Customer");
                    Response.Clear();
                    Response.Buffer = true;
                    Response.Charset = "";
                    Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                    Response.AddHeader("content-disposition", "attachment;filename=Customer_Creation.xlsx");
                    using (MemoryStream MyMemoryStream = new MemoryStream())
                    {
                        wb.SaveAs(MyMemoryStream);
                        MyMemoryStream.WriteTo(Response.OutputStream);
                        Response.Flush();
                        Response.End();
                    }
                }
                lblMessage.Visible = false;
            }
            catch (Exception ex)
            {
                lblMessage.Text = ex.Message;
                lblMessage.Visible = true;
            }
        }

        public DataTable BindComboWithParm(Hashtable ht, string sp)
        {
            try
            {
                command = new SqlCommand();
                command.CommandType = CommandType.StoredProcedure;
                command.CommandText = sp;
                command.Connection = connection;
                SqlDataAdapter Adp = new SqlDataAdapter(command);
                Dt = new DataTable();
                Adp.Fill(Dt);
                lblMessage.Visible = false;
            }
            catch (Exception ex)
            {
                lblMessage.Text = ex.Message;
                lblMessage.Visible = true;                
            }

            return Dt;
        }