C#NET2008 How to Save a EXCEL Spreadsheet after creating and filled it

    using Microsoft.Office.Interop.Excel;

   // --- Declare EXCEL Objects ---
   Microsoft.Office.Interop.Excel.Application xlExcel = null;
   Microsoft.Office.Interop.Excel.Workbook xlWrkBook;
   Microsoft.Office.Interop.Excel.Worksheet xlWrkSheet;
   Microsoft.Office.Interop.Excel.Range xlRange;
   Microsoft.Office.Interop.Excel.Range xlWrkSheet_Range;

  // --- Instantiate EXCEL Object ---
     xlExcel = new Microsoft.Office.Interop.Excel.Application();
     xlWrkBook = xlExcel.Workbooks.Add(OMissing);
     xlWrkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWrkBook.Worksheets.get_Item(1);
     xlExcel.Visible = true;

  while (DR.Read())
   {
     introw += 1;
     xlWrkSheet.Cells[introw, 1] = DR["OrderID"];
     xlWrkSheet.Cells[introw, 2] = DR["OrderDate"];
     xlWrkSheet.Cells[introw, 3] = DR["RequiredDate"];
     xlWrkSheet.Cells[introw, 4] = DR["ShipDate"];
     xlWrkSheet.Cells[introw, 5] = DR["shipperName"];  // Shipper Name
     xlWrkSheet.Cells[introw, 6] = DR["ProductName"];
     xlWrkSheet.Cells[introw, 7] = DR["UnitPrice"];
     xlWrkSheet.Cells[introw, 8] = DR["Discount"];
     xlWrkSheet.Cells[introw, 9] = DR["ExtendedPrice"];
     xlWrkSheet.Cells[introw, 10] = DR["Freight"];
 
  } //end while

// --- Folder Path and Excel Name ---
   string folderPath = "C:\ExcelFolder\;
   string ExcelName = "Invoice.xls";
   string FullName  = folderPath + ExcelName

   HOW TO SAVE THE FULLNAME ?

Thank you for your help. Appreciate that very much for helping me.

Cheers,

Lennie