Export Excel asp.net (C#) ใครพอทราบการ export ข้อมูลจาก GridView ออกมาเป็นไฟล์ Excel ด้วยครับ

try
			{			
				// Get the datatable to export			
				DataTable dtEmployee = dsEmployee.Tables["Employee"].Copy();

				// Export all the details to Excel
				RKLib.ExportData.Export objExport = new RKLib.ExportData.Export("Win");				
				objExport.ExportDetails(dtEmployee, Export.ExportFormat.Excel, "C:\\EmployeesInfo.xls");
				lblMessage.Text = "Successfully exported to C:\\EmployeesInfo.xls";
			}
			catch(Exception Ex)
			{
				lblMessage.Text = Ex.Message;
			}

string connectionStringFL = String.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=YES;""",PartFiel/MyExcel.xls);
string connectionString = String.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=YES;""", FileUpload1.PostedFile.FileName);
string query = String.Format("SELECT * FROM [Sheet1$]");

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using Excel = Microsoft.Office.Interop.Excel; 

namespace ExcelC
{
    public partial class frmExcel : Form
    {
        public frmExcel()
        {
            InitializeComponent();
        }

        private void btnExcel_Click(object sender, EventArgs e)
        {
            Excel.Application xlApp;
            Excel.Workbook xlWorkBook;
            Excel.Worksheet xlWorkSheet;
            object mis = Type.Missing;

            string strFileName = "C:\\ExcelC\\Xls\\GenExcel.xls";

            xlApp = new Excel.ApplicationClass();
            xlWorkBook = xlApp.Workbooks.Add(mis);
     
            //xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.Add(mis, mis, mis, mis); /*** for Add New Sheet ***/
            xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
            xlWorkSheet.Name = "My Sheet";
            xlWorkSheet.Cells[1, 1] = "www.ThaiCreate.Com";
            xlWorkSheet.Cells[2, 1] = "Mr.Weerachai Nukitram";

            xlWorkBook.SaveAs(strFileName,
                mis, mis, mis, mis, mis, Excel.XlSaveAsAccessMode.xlExclusive, mis, mis, mis, mis, mis);
            xlWorkBook.Close(true, mis, mis);
            xlApp.Quit();

            System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkBook);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkSheet);

            xlApp = null;
            xlWorkBook = null;
            xlWorkSheet = null;
            GC.Collect();

            MessageBox.Show("Generate Successfully");

        }

    }
}