相反，使用的 Excel.Workbook.Sheets 集合，它更容易访问的Excel.Workbook.Worksheets 收集，这样你可以利用早期绑定。

Instead of the using Excel.Workbook.Sheets collection, it's easier to access the Excel.Workbook.Worksheets collection, that way you can utilize early binding.

在你的情况，它可能看起来像下面这样：

In your case, it could look something like the following:

Excel.Application excelApp = new Excel.Application();
excelApp.Visible = true;

Excel.Workbook workbook = excelApp.Workbooks.Open("C:\MyWorkbook.xls",
    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);

// The key line:
Excel.Worksheet worksheet = (Excel.Worksheet)workbook.Worksheets["SubSignOff"];

希望这有助于...

Hope this helps...