哪位大哥帮帮忙！ .net 获取客户端excel中的某个单元值 出错！

[MaNyDoDo]

......

Excel.ApplicationClass myApp;
Excel.Workbook myBook;
Excel.Worksheet mySheet;
myApp=new Excel.ApplicationClass();
myApp.Visible = false;
object oMissiong = System.Reflection.Missing.Value;
myApp.Workbooks.Open("c:\\1.xls",oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong,oMissiong);
myBook=myApp.Workbooks[1];
mySheet=(Excel.Worksheet)myBook.Sheets[1];

strXh = mySheet.Cells[1,1].ToString();

......

监视结果:
strXh 值:"System.__ComObject"
mySheet.Cells[intRow,1] 值:错误：“mySheet.Cells”不存在