如何使用getActiveObject（“Excel.Application”）

I need to finish an application in C#. Now I want to get a function that control a Excel file to get data. I used getActiveObject("Excel.Application"), but this returns nothing. And more, I can't use Excel.Application in VS2008 , and Microsoft.Office.Interop.Excel.Application is instead of it. So is there another way to get what I want? I need to finish an application in C#. Now I wa