Getting two excel files into ONE Excel Work Book

I have Already Got my data pulled from Datatable & Dataset into Excel Sheet using Export Excel Cocept ,for each datatable and Dataset i am getting a Excel Sheet Ready. Is there any way that i can get all the sheets in a single Excel WorkBook using (c#)

   protected void UploadDataTableToExcel(DataTable dtEmp, string filename)
   {
       string attachment = "attachment; filename=" + filename;
       Response.ClearContent();
       Response.AddHeader("content-disposition", attachment);
       Response.ContentType = "application/vnd.ms-excel";
       string tab = string.Empty;
       foreach (DataColumn dtcol in dtEmp.Columns)
       {
           Response.Write(tab + dtcol.ColumnName);
           tab = "\t";
       }
       Response.Write("\n");
       foreach (DataRow dr in dtEmp.Rows)
       {
           tab = "";
           for (int j = 0; j < dtEmp.Columns.Count; j++)
           {
               Response.Write(tab + Convert.ToString(dr[j]));
               tab = "\t";
           }
           Response.Write("\n");
       }
       Response.End();
       }


       protected void lnkExport_Click(object sender, EventArgs e)
        {
          DataTable dt = new DataTable();
          DataSet ds = new DataSet();
          string funcName = (string)ViewState["Reports"];
          if (funcName == "DataTable1")
          dt = DbAccess.GetDataTable1();
          else if (funcName == "DataTable2")
            dt = DbAccess.GetDataTable2();

          if (ds.Tables.Count > 0)
          {
             string strFilename = funcName + ".xls";
             UploadDataSetToExcel(ds, strFilename);
          }
           else
          {

            string strFilenames = funcName + ".xls";
            UploadDataTableToExcel(dt, strFilenames);
          }

Solution

You can use the Office.Excel interop to move the sheets to a single workbook after creating them and saving the workbook. This opens two workbooks and copy one sheet from the first workbook into the second one then save the second workbook:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Excel = Microsoft.Office.Interop.Excel;

namespace MergeBooks
{
    class Program
    {
        static void Main(string[] args)
        {
            Excel.Application exApp = new Excel.Application();
            Excel.Workbook wb1 = exApp.Workbooks.Open(@"C:\wb1.xls");
            Excel.Workbook wb2 = exApp.Workbooks.Open(@"C:\wb2.xls");
            Excel.Worksheet worksheet1 = wb1.Worksheets[1];
            Excel.Worksheet worksheet2 = wb2.Worksheets[1];
            worksheet1.Copy(worksheet2);
            wb2.SaveAs(@"C:\wb3.xls");

            wb1.Close(false);
            wb2.Close(false);
            exApp.Quit();

        }
    }
}