C# Excel process won't close

Question

I'm writing a program where you can enter stuff into an excel via a button. When the button is pressed the Application is started it interacts with the spreadsheet.

But when it's finished interacting the process should be closed completely but it hangs in the Task Manager.

I've tried numerous solutions to close it but it won't.

Here is my code

  using Microsoft.Office.Interop.Excel;
  using System.Linq;
  using System.Runtime.InteropServices;
  using Application = Microsoft.Office.Interop.Excel.Application;

  .
  .
  .
  .

  Application oxl = null;
  Workbooks wbs = null;
  Workbook wb = null;
  Worksheet ws = null;
  Sheets wss = null;
  Range r = null;
  Range orange2 = null;
  Range resultRange = null;


  try {
   oxl = new Application();
   wbs = oxl.Workbooks;
   wb = wbs.Open(Settings.Default.excelPath);
   wss = wb.Worksheets;
   ws = (Worksheet) wss[2];

   r = ws.Range["A2:A924"];
   foreach(string tofind in tofinds) {
    resultRange = null;
    string[] s = data[tofind];

    resultRange = r.Find(
     What: tofind,
     LookIn: XlFindLookIn.xlValues,
     LookAt: XlLookAt.xlPart,
     SearchOrder: XlSearchOrder.xlByRows,
     SearchDirection: XlSearchDirection.xlPrevious,
     MatchCase: true);

    if (resultRange != null) {
     int i = resultRange.Row;
     orange2 = ws.Cells[i, 2];

     if (orange2.Value == null) {
      orange2 = ws.Cells[i, 2];
      //s[0]= -3.94e6
      orange2.Value = s[0].Split((char)
       'e')[0].Replace("-", "");
      orange2.NumberFormat = "0.00";

     }
    } else {
     //Log to Console
    }



   }

   wb.Save();

  } catch (IOException e) {
   Console.WriteLine(e.Message);
  } finally {

   Marshal.FinalReleaseComObject(orange2);
   Marshal.FinalReleaseComObject(r);
   Marshal.FinalReleaseComObject(resultRange);

   orange2 = null;
   r = null;
   resultRange = null;



   foreach(Worksheet sheet in wss) {
    Marshal.FinalReleaseComObject(sheet);
   }

   Marshal.FinalReleaseComObject(wss);
   wss = null;

   wb.Close(0);
   wbs.Close();

   foreach(Workbook workbook in wbs) {
    Marshal.FinalReleaseComObject(workbook);
   }

   Marshal.FinalReleaseComObject(wb);
   wb = null;

   Marshal.FinalReleaseComObject(wbs);
   wbs = null;

   oxl.Application.Quit();
   oxl.Quit();

   Marshal.FinalReleaseComObject(oxl);

   oxl = null;


   GC.Collect();
   GC.WaitForPendingFinalizers();
   GC.Collect();
   GC.WaitForPendingFinalizers();
   Console.WriteLine("Final");
  }

Remove the zero from the WB.Close() Also remove the wbs.Close(); which is not needed and will give an error if after the WB.Close() since the workbook doesn't existing. — jdweng, Jun 08 '20 at 11:11
Does this help you? [link](https://stackoverflow.com/questions/27930307/why-does-microsoft-office-interop-excel-application-quit-leave-the-background) — Yosef Bernal, Jun 08 '20 at 11:12
@jdweng I don't get any error and removing the 0 has no impact on the problem — Triims, Jun 08 '20 at 11:27
@YosefBernal already tried that. And I don't want to use the sledge hammer methode by killing the process — Triims, Jun 08 '20 at 11:28
Did you post all your excel code? Some methods create new workbooks and you may of create more than one workbook. the workbooks could be closing but the application oxl is not closing. Or you could be getting an exception. It may be some of your attempts to fix the problem is causing exceptions and making the issue worse. It may be better to comment out all the code that is not really needed and start from the beginning. — jdweng, Jun 08 '20 at 11:36
there are only a few more of this orange2 = ws.Cells[i, 2]; //s[0]= -3.94e6 orange2.Value = s[0].Split((char) 'e')[0].Replace("-", ""); orange2.NumberFormat = "0.00"; — Triims, Jun 08 '20 at 12:02
FWIW, I have an application on a different platform that interacts with Word using COM objects, and since Office2016 was introduced, I have this same problem. I finally gave up and wrote a program to work for the .EXE in running tasks and if it had been running for 15 minutes, I killed it. — Duston, Jun 08 '20 at 13:07

score 1 · Answer 1 · answered Jun 08 '20 at 14:00

Found the Solution. If you get your Range by

Range r = sheet.Cells[1,1];
Marshal.FinalReleaseComObject(r);
r = null;

Cells[1,1] creates an own COM object

Rang r1 = sheet.Cells;
Range r = r1[1,1];
Marshal.FinalReleaseComObject(r1);
r1 = null;
Marshal.FinalReleaseComObject(r1);
r1 = null;

by doing that it worked for me

C# Excel process won't close

1 Answers1