怎样用.net读出Excel的多个Sheet

            Application app = new Application();
            Workbooks workbooks = app.Workbooks;
            Workbook workbook = 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);
            Sheets excelSheets = workbook.Worksheets;
          
            for (int i = 1; i <= excelSheets.Count; i++)
            {
                _Worksheet m_objSheet = (_Worksheet)(excelSheets.get_Item(i));
                if (AllSheet == "") AllSheet = m_objSheet.Name;
                else AllSheet += "," + m_objSheet.Name;
            }

            workbooks.Close();
            app.Quit();