CODEWITHSUNDEEP
c#winformsms-wordoffice-interop
TmZn
TmZn

Reputation: 407

Word interop Document takes time to close, not able to delete temporary files

I'm building a C# WinForm application to edit a word document template (amongst other features). Since I have to insert a couple of images, I create a copy of them in the temp folder of the computer(from a database request) and want to delete all of those files when closing the app.

It seems like closing the actual document and ApplicationClass of Office.Interop.Word takes some time, and I would like to know if there's a way to trigger an event or anything similar when the application is actually closed.

Here's my function :

private void CloseDocument()
{
    if (_doc != null)
    {
        _doc.Close();
        _doc = null;
    }

    if (_appClass != null)
    {
        _appClass.Quit();
        _appClass = null;
    }

    File.Delete(tempFileName);

    foreach (string path in _imagePaths)
    {
        File.Delete(path);
    }
}

This function is binded to the OnHandleDestroyed Event. Unfortunately, when the document contains a bunch of images, it seems like it takes some times for the _doc and _appClass objects to actually close, leading the program to throw a System.IO.IOException : The process cannot access the file 'C:\Users\***\AppData\Local\Temp\alr1snsc.png' because it is being used by another process.

Is there any way to actually trigger a function when the document or ApplicationClass is properly close ? Note that if I insert a sleep before trying to delete the files, everything works fine, this is why I came to the conclusion that it's really about properly closing the document.

Upvotes: 0

Views: 646

Answers (2)

Edney Holder
Edney Holder

Reputation: 1228

There is no built in way to do what you are looking to do. Although it is a common need, Microsoft has yet to address it. Because of this there are a couple of hacks that are common to accomplish this.

1) Check for the temp file in a loop. Once it is gone you can delete your files.

string fileName = "~" + <YourDocumentFileName>
                do
                {

                } while (File.Exists(fileName));

2) Try to reference something in the document and when it fails you can delete the files.

bool docClosed = false;
                string fileName;
                do
                {
                    try
                    {
                        fileName = _doc.OriginalDocumentTitle;
                    }
                    catch(Exception ex)
                    {
                        docClosed = true;
                    }
                } while (!docClosed);

Upvotes: 2

Cindy Meister
Cindy Meister

Reputation: 25663

This is a common issue with Word. There is no event, as such, in the Word object model to inform when file locks have been released. (I find it odd, however, that this would apply to image files, normally, I only associate this problem with Word files and linked content.)

One very important thing is that the code release the COM objects explicitly and run GC. If this doesn't happen, the file locks won't be released before the calling application goes out of scope (quits and cleans up), if then. The code in the question appears to release the objects, but it doesn't garbage collect. For an example, see this answer.

Very often, the strategy for this problem is to check for these files the next time the application runs and delete them then.

Another possibility would be to check for the presence of the related "temp" file Word opens when a document is opened. This will be in the same folder as the document and the file name starts with a tilde (~). When that disappears from the folder, the file lock should be gone. So a loop checking for that could work.

I suspect that the Windows API (or even the .NET Framework) might provide a function to detect file locks...

Upvotes: 2

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