从c＃

Question

我已经阅读了几篇有关从.NET进行交互时正确处理COM对象的文章/帖子。通常我没有问题..但是我关闭下面的程序后仍然收到孤立的COM对象。我不知道它是否与我打开的插件有关。

        Application app = new Application();
        Workbooks wrks = app.Workbooks;
        Workbook wrk = null;
        Workbook wrkAddin = null;
        Sheets shts = null;
        Range rng = null;           

        try
        {
            app.ScreenUpdating = true;
            app.Visible = true;
            app.DisplayAlerts = false; // stop any dialog boxes appearing.. such as save or debug when loading bloomberg addin.
            wrk = wrks.Open(Filename: MasterPriceFiles.Properties.Resources.strETFDataFullPath, ReadOnly: false,Editable: true, IgnoreReadOnlyRecommended: true);
            Thread.Sleep(500);
            wrkAddin = wrks.Open(Filename: MasterPriceFiles.Properties.Resources.strBloombergAddinPath); // have to explicitly open the bloomberg addin
            app.Visible = true;
            Thread.Sleep(50000);
            shts = wrk.Worksheets;
            foreach (Worksheet sht in shts)
            {
                rng = sht.UsedRange;
                rng.Copy();
                rng.PasteSpecial(XlPasteType.xlPasteValues);
                Marshal.ReleaseComObject(rng);
                Marshal.ReleaseComObject(sht);
            }
            app.Visible = false;
            app.DisplayAlerts = false;
            Thread.Sleep(500);
            wrk.SaveAs(Filename: MasterPriceFiles.Properties.Resources.strETFDataMacroFreeFullPath, ConflictResolution: XlSaveConflictResolution.xlLocalSessionChanges, AccessMode: XlSaveAsAccessMode.xlNoChange);
            Console.WriteLine("Successfully saved ETF price data sheet at . " + DateTime.Now.ToString());


        }
        catch(Exception ex)
        {
            Console.WriteLine("Error refreshing ETF price date. " + ex.Message);
        }
        finally
        {
            if (rng != null) Marshal.FinalReleaseComObject(rng);
            if (shts != null) Marshal.FinalReleaseComObject(shts);
            wrk.Close(SaveChanges: false);
            if (wrk != null) Marshal.FinalReleaseComObject(wrk);
            wrkAddin.Close(SaveChanges: false);
            if (wrkAddin != null) Marshal.FinalReleaseComObject(wrkAddin);
            if (wrks != null) Marshal.FinalReleaseComObject(wrks);
            app.Quit();
            if (app != null) Marshal.FinalReleaseComObject(app);
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }