Lingering Excel Process

Question

I am doing a Windows Service, and I am using Microsoft.Office.Interop.Excel to create a new excel file, edit it, and save it.

After being done with it, and closing the appropriate objects (worksheet, workbook), quitting the excel app, and Marshal releasing COM objects, the process is still lingering.

    private void doWork()
    {
        var excelApp = new MsExcel.Application();
        var workBooks = excelApp.Workbooks;
        var workbook = excelApp.Workbooks.Add();
        var sheets = workbook.Sheets;
        _worksheet = workbook.Sheets[1];

        //Do Work Here

        _worksheet.SaveAs(filePath);
        workbook.Close(false,System.Reflection.Missing.Value,System.Reflection.Missing.Value);
        workBooks.Close();
        releaseObject(_worksheet);
        releaseObject(sheets);
        releaseObject(workbook);
        releaseObject(workBooks);
        excelApp.Quit();
        releaseObject(excelApp);

    }

    private void releaseObject(object obj)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        }
        catch (Exception ex)
        {
            _log.Error($"Unable to release object {obj} Error:" + ex.ToString());
            obj = null;
        }
        finally
        {
            GC.Collect();
        }
    }

I saw a couple of other posts that suggested the releasing of the objects, plus the reference to Workbooks and Sheets. Not sure, why this is still not working.

Answer 1

Microsoft does not currently recommend, and does not support, Automation of Microsoft Office applications from any unattended, non-interactive client application or component (including ASP, ASP.NET, DCOM, and NT Services), because Office may exhibit unstable behavior and/or deadlock when Office is run in this environment.

If you are building a solution that runs in a server-side context, you should try to use components that have been made safe for unattended execution. Or, you should try to find alternatives that allow at least part of the code to run client-side. If you use an Office application from a server-side solution, the application will lack many of the necessary capabilities to run successfully. Additionally, you will be taking risks with the stability of your overall solution. Read more about that in the Considerations for server-side Automation of Office article.

As a workaround you may consider using One XML SDK or any other third-party components designed for the server-side or service execution.