Qt: Could not initialize OLE (error 80010106)

I’m working on a ASP.NET Core MVC app and I wanted to use DinkToPdf library to convert Html to PDF. I get this error in the console, when I first access a page that uses the IConverter from the services:

Qt: Could not initialize OLE (error 80010106)

I still get the PDF with no issues. I think the issue is somewhere around calling: new SynchronizedConverter(new PdfTools()) As I have it in the services as a singleton and only called the first time it’s accessed:

services.AddSingleton(typeof(IConverter), new SynchronizedConverter(new PdfTools()));

[distantcam]

I’ve just hit this problem too, in an Azure Isolated Functions host project.

I’m pretty sure this issue is due to the worker thread in SynchronizedConverter not being STA mode. So I copied the SynchronizedConverter and made an STA version.

public class STASynchronizedConverter : BasicConverter
{
    Thread conversionThread;

    BlockingCollection<Task> conversions = new BlockingCollection<Task>();

    bool kill = false;

    private readonly object startLock = new object();

    public STASynchronizedConverter(ITools tools) : base(tools)
    {
    }

    public override byte[] Convert(IDocument document)
    {
        return Invoke(() => base.Convert(document));
    }

    public TResult Invoke<TResult>(Func<TResult> @delegate)
    {
        StartThread();

        Task<TResult> task = new Task<TResult>(@delegate);

        lock (task)
        {
            //add task to blocking collection
            conversions.Add(task);

            //wait for task to be processed by conversion thread
            Monitor.Wait(task);
        }

        //throw exception that happened during conversion
        if (task.Exception != null)
        {
            throw task.Exception;
        }

        return task.Result;
    }

    private void StartThread()
    {
        lock (startLock)
        {
            if (conversionThread == null)
            {
                conversionThread = new Thread(Run)
                {
                    IsBackground = true,
                    Name = "wkhtmltopdf worker thread"
                };

                // This is to fix issue https://github.com/rdvojmoc/DinkToPdf/issues/119
                conversionThread.SetApartmentState(ApartmentState.STA);

                kill = false;

                conversionThread.Start();
            }
        }
    }

    private void StopThread()
    {
        lock (startLock)
        {
            if (conversionThread != null)
            {
                kill = true;

                while (conversionThread.ThreadState == ThreadState.Stopped)
                { }

                conversionThread = null;
            }
        }
    }

    private void Run()
    {
        while (!kill)
        {
            //get next conversion taks from blocking collection
            Task task = conversions.Take();

            lock (task)
            {
                //run taks on thread that called RunSynchronously method
                task.RunSynchronously();

                //notify caller thread that task is completed
                Monitor.Pulse(task);
            }
        }
    }
}

[zanyar3]

Thanks, @distantcam it is work.

only notice for all, To access the Converter class, you must inject it, not create a new instance.

public YourService(IIConverter converter) 
{
        _converter = converter;
}