Microsoft.Office.Interop.Excel.Application objExcel = new Microsoft.Office.Interop.Excel.Application();
Microsoft.Office.Interop.Excel._Workbook objBook = objExcel.Workbooks.Open(
fileName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);