是否可以将Excel应用程序对象设置为指向已经打开的Excel实例？

Question

I am currently trying to create an export tool to push data into Excel. However after the first push, Excel is left open, and sometimes a user may want to leave Excel open while they push more data to another page in the same excel sheet. I usually just release the COM objects once the export is done. The way my methods work right now involves opening a new instance of excel every time I export...

would it be beneficial to create a global instance of the application to use continuiously from the point I begin exporting until the point of the Excel application being closed?

Should I be using event handlers to detect when Excel has been closed so I know when to release the COM objects?

If I do try to make a global instance of an Excel Application, I can instantiate it and wait to release it, that way I don't need to try and find open instances of excel again.. but if I needed to find, and assign to a variable, an open instance of Excel (that has previously existed in code but had the COM objects released), how would I do this?

Answer 1

I have used this in the past. tPath is the path to my excel file that should be opened/reused.

Dim exApp As New Excel.Application

'finds the workbook.  If it is already open, then it uses that.  Otherwise, it opens in new instance
Dim wb As Excel.Workbook
wb = System.Runtime.InteropServices.Marshal.BindToMoniker(tPath)
exApp = wb.Parent

Answer 2

You can use the Interop Library to point to the open excel-app

(This code is written in C# so there could be some minor change for VB.Net)

oExcel = (Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application")