Generating and Exporting an Excel File in ASP.NET - Using Excel COM Object

Here is the code

Microsoft.Office.Interop.Excel.ApplicationClass objExcelApp = null;
Microsoft.Office.Interop.Excel.Workbook objWBook = null;
Microsoft.Office.Interop.Excel._Worksheet objWorksheet = null; 

  try
   {
        objExcelApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
        //Hiding Excel Application
        objExcelApp.Visible = false; 
        //Hiding All the alert messages        
        objExcelApp.DisplayAlerts = false;         

        // Add Work Book   

        objWBook = objExcelApp.Application.Workbooks.Add(System.Reflection.Missing.Value);                        

         objWorksheet = (Microsoft.Office.Interop.Excel._Worksheet)objWBook.Sheets[1];

         objWorksheet.Name = "WorkSheet Name";

        string[] sExcelRow = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };                       

        // write column names

        for (int intCounter = 0; intCounter < 2; intCounter++)
              {
                  objExcelApp.Cells[1, intCounter + 1] =  “ColumnName"; 

//  Specify Number format –  Excel considers ‘01' as number and truncate leading
 // zero. To  retain leading zero, mention number format. 
    objWorksheet.get_Range(Convert.ToString(sExcelRow[intCounter]) +   Convert.ToString(intCounter + 1),                       Convert.ToString(sExcelRow[intCounter] + Convert.ToString(intCounter + 1))).EntireColumn.NumberFormat = "@";

               }                  

           for (int intCounter = 0; intCounter < DataTable/Collection.Rows.Count; intCounter ++)
              {
                  objExcelApp.Cells[intCounter + 2, 1] =  “Data “; 
                  objExcelApp.Cells[intCounter + 2, 2] =  “Data “;               
               }
           // AutoFit Columns     
           objExcelApp.Columns.AutoFit();
          //Store Excel file at any physical location
         String strFilePath = System.IO.Path.Combine(DIRECTORY,FILENAME);
         objWBook.SaveAs(Server.MapPath(strFilePath),                              Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
System.Reflection.Missing.Value, System.Reflection.Missing.Value,
System.Reflection.Missing.Value, System.Reflection.Missing.Value, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,System.Reflection.Missing.Value, System.Reflection.Missing.Value,System.Reflection.Missing.Value, System.Reflection.Missing.Value,System.Reflection.Missing.Value);                       

//Close Excel Work Book   and Quit Application
  objWBook.Close(false, System.Reflection.Missing.Value, System.Reflection.Missing.Value);
  objExcelApp.Workbooks.Close();
  objExcelApp.Quit(); 

    HttpContext.Current.Response.Clear();
    HttpContext.Current.Response.ClearContent();
    HttpContext.Current.Response.ClearHeaders();
    HttpContext.Current.Response.AddHeader("content-disposition", string.Format("attachment; filename={0}", fileName));
    HttpContext.Current.Response.ContentType = "application/excel";
    HttpContext.Current.Response.WriteFile(Server.MapPath(strFilePath));
    HttpContext.Current.Response.End();
     }

     catch (Exception ex)
       {
             CommonUtility.DisplayExceptionMessage(ex);
       }
       finally
       {
          //Release  Excel COM Objects                System.Runtime.InteropServices.Marshal.ReleaseComObject(objWorksheet);                System.Runtime.InteropServices.Marshal.ReleaseComObject(objWBook);                System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp);
          objWorksheet = null;
          objWBook = null;
          objExcelApp = null;
          GC.Collect();
          GC.WaitForPendingFinalizers();
     }