Why does calling Quit() on an Interop.Excel.Application in a .Net application not terminate the process?

Posted on 2013-10-28
Last Modified: 2013-10-28

I'm having issues using Microsoft Interop.Excel.Application in my .Net program.

Consider the following code snippet:
                // Open to force Excel to perform calculation itself
                Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();
                //excelApp.WindowState = Microsoft.Office.Interop.Excel.XlWindowState.xlMinimized;
                var excelWorkbook = excelApp.Workbooks.Open(tempFileName);
                excelApp = null;

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When I check in Task Manager, I notice that the EXCEL.EXE task created by the above code snippet does not terminate.

I'm not directly accessing any of the worksheets.
For my purposes all I need to do is:
1) Launch the application (which will force a recalc on open)
2) Save the spreadsheet
3) Terminate the application

What am I missing here?
Is there some sort of COM object that needs to be released?

Question by:jxbma
LVL 81

Expert Comment

by:zorvek (Kevin Jones)
ID: 39606863
Did you try closing the workbook after saving it so that there are no open workbooks when invoking the Quit method?


Expert Comment

ID: 39606927
You may need to kill the excel process.

Process[] AllProcesses = Process.GetProcessesByName("excel");
// check to kill the right process
  foreach ( Process ExcelProcess in AllProcesses)
    if (myHashtable.ContainsKey(ExcelProcess.Id) == false)
AllProcesses = null;

Ref Link:

Hope this helps.
LVL 21

Accepted Solution

Boyd (HiTechCoach) Trimmell, Microsoft Access MVP earned 500 total points
ID: 39606998
It sounds like you code may be starting two instances of Excel and only closing one.

You may also want to check out this:
How to open an Excel file in C#

Author Closing Comment

ID: 39607078
There are not 2 instances of Excel running.

I just need to do a release on the workbook and application COM objects.
Thanks for pointing me in the right direction.


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