Question

1. When i started my app and opened word file i see 3 process winword.exe in taskmanager.
   After i called ‘close’ function 1 process winword.exe closed.

2. When i called worddoc.close() or wordapp.quit() in destructor, i got exception “COM object that has been separated from its underlying RCW cannot be used.”

public class WordHelper
{
    private object nullobj = System.Reflection.Missing.Value;

    public string context = "";

    Microsoft.Office.Interop.Word.Document doc = new Document();
    Microsoft.Office.Interop.Word.Application wordApp = new Application();

    public WordHelper(string FileName)
    {
           //Open word file
    }

    //somefunction fo work with file

    public void CloseWord()
    {
        doc.Close();
        wordApp.Quit();
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(wordApp);
    }

    ~WordHelper()
    {
        //i got exception
        doc.Close();
        wordApp.Quit();
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(wordApp);
    }
}

How i call my class

        WordHelper wddoc = new WordHelper("C:\\Test Word\\Test.docx");
        wddoc.CloseWord(); //this line i use and can close 1 process not 3
        //One process close after i close application

At the end i want close all winword.exe which was opened by my application, and i want to close them in destructor. At the end, i need to close all ‘winword.exe’ which was opened by my application, and i need to close them in destructor.

Answer 1

You are doing this in a finalizer (different than a destructor). Finalizers are non-deterministic, meaning by the time they run class members may have already been finalized and thus would no longer be valid.

I would implement the Dispose pattern and explicitly control the lifetime of your word COM objects. This answer has a lot of good links that may help you.