CODEWITHSUNDEEP
c#multithreading
captainmoose
captainmoose

Reputation: 41

C# thread hangs on close file

I have a thread that calls a static method to update file properties using WindowsAPICodePack ShellPropertyWriter and BackgroundWorker. The thread calls the method below for each file in a folder of 1000+ files and hangs on the ShellPropertyWriter.close() after the 700th update or so.

Nothing to do with the file itself, tried using different files that successfully updated before.

    public static bool ShellPropertyUpdate(VideoEntry mediaEntry)
    {
        try
        {
            ShellFile mediafile = ShellFile.FromFilePath(mediaEntry.FilePath);
            ShellPropertyWriter pw = mediafile.Properties.GetPropertyWriter();
            pw.WriteProperty(SystemProperties.System.Music.Artist, mediaEntry.Actor);
            pw.WriteProperty(SystemProperties.System.Music.Genre, mediaEntry.Genre);
            pw.WriteProperty(SystemProperties.System.Rating, mediaEntry.Rating);
            pw.Close();
        }
        catch (Exception ex)
        {
           return false;
        }
        return true;
    }

    private void mnuWriteMetadataToFiles_Click(object sender, EventArgs ev)
    {
        this.WorkerThread = new BackgroundWorker();
        this.WorkerThread.DoWork += new DoWorkEventHandler(WorkerThread_WriteMetadataToFiles);
        this.WorkerThread.ProgressChanged += new ProgressChangedEventHandler(WorkerThread_ProgressChanged);
        this.WorkerThread.RunWorkerCompleted += (s, e) => WorkerThread_Completed("Writing metadata to files", s, e);
        this.WorkerThread.WorkerReportsProgress = true;
        this.WorkerThread.WorkerSupportsCancellation = true;
        this.WorkerThread.RunWorkerAsync(WMPlayer);
    }

    private void WorkerThread_WriteMetadataToFiles(object sender, DoWorkEventArgs e)
    {
        int counter = 0;
        BackgroundWorker worker = (BackgroundWorker)sender;
        MediaPlayer wmp = (MediaPlayer)e.Argument;

        // ... Loop with the foreach video in the library and write it to file.
        foreach (VideoEntry entry in wmp.Videos)
        {
            if (worker.CancellationPending)
            {
                e.Cancel = true;
            }
            else
            {
                worker.ReportProgress(counter, "Updating '" + entry.Filename + "'" + Environment.NewLine + "Processing file");
                if (VideoToFile.ShellPropertyUpdate(entry))
                {
                    result &= true;
                }
                counter++;
            }
        }
        e.Result = result;
    }

Upvotes: 4

Views: 261

Answers (3)

Rob Accardi
Rob Accardi

Reputation: 51

I was having the same problem, but in my case I had reason to believe it was NOT related to any particular file being used to create a ShellFile object. Instead, the exception would occur whenever the ShellFile object was Disposed: if I limited the scope of the object using a "using" block, the exception would occur immediately upon existing that block; and if I manually called .Dispose() on the object, the exception would happen right then and there. I managed to fix this by changing from aybe's version of Microsoft-WindowsAPICorePack (1.1) over to contre's version (1.1.5)

I removed both aybe packages I had installed (...Core and ...Shell) using dotnet remove package. Then I added the contre packages using dotnet add package Microsoft-WindowsAPICodePack-Core --version 1.1.5 dotnet add package Microsoft-WindowsAPICodePack-Shell --version 1.1.5 I then had to update my project.csproj file such that the target framework is now set to net8.0-windows instead of net8.0

and in doing this, I also had to adjust my launch.json such that the "program" attribute now pointed to the /net8.0-windows/ subfolder.

Upvotes: 0

captainmoose
captainmoose

Reputation: 41

Apparently it does have something to do with the files themselves. I took out few problem files and the Thread continued processing until the next problem file. I have no clue what's wrong with the file, however I'm willing to pass on updating problem files. Is there a way to stop/kill the thread? I can't use DoWorkEventArgs.cancel() since the thread is hanging and not coming back.

Upvotes: 0

Dialecticus
Dialecticus

Reputation: 16761

Never heard of this assembly before, but it smells like handle exhaustion to me. Try this instead:

using (ShellFile mediafile = ShellFile.FromFilePath(mediaEntry.FilePath))
{
    ShellPropertyWriter pw = mediafile.Properties.GetPropertyWriter();
    pw.WriteProperty(SystemProperties.System.Music.Artist, mediaEntry.Actor);
    pw.WriteProperty(SystemProperties.System.Music.Genre, mediaEntry.Genre);
    pw.WriteProperty(SystemProperties.System.Rating, mediaEntry.Rating);
    pw.Close();
}

Here every file handle is closed immediately, instead of at garbage collector's discretion. ShellFile must implement IDisposable for this to work, otherwise this code will not compile. I'm fairly certain that ShellFile implements it.

Upvotes: 3

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