How To Ignore Access Violation Exception From External Dll - .NET Core 6

Question

I'm using DinkToPDF dll to convert an XML to PDF.

I need to generate 2000 PDF's.

So I try to do put the PDF generation logic inside for loop. It generates first 2 or 3 PDF's and then in the next iteration crashes with a native Exception

This is my PDF generation class. Generate() method will be called 2000 times inside a forloop

public static class PDFEngine
{
    public static void Generate(string html, string directory, string fileName)
    {
        var converter = new BasicConverter(new PdfTools());

        converter.PhaseChanged += Converter_PhaseChanged;
        converter.ProgressChanged += Converter_ProgressChanged;
        converter.Finished += Converter_Finished;
        converter.Warning += Converter_Warning;
        converter.Error += Converter_Error;

        var doc = new HtmlToPdfDocument()
        {
            GlobalSettings = {
                ColorMode = ColorMode.Color,
                Orientation = Orientation.Portrait,
                PaperSize = PaperKind.A4,
            },
            Objects = {
                new ObjectSettings() {
                    PagesCount = true,
                    HtmlContent = html,
                    WebSettings = { DefaultEncoding = "utf-8" },
                    HeaderSettings = { FontSize = 9, Right = "Page [page] of [toPage]", Line = true },
                    FooterSettings = { FontSize = 9, Right = "Page [page] of [toPage]" }
                }
            }
        };

        byte[] pdf = converter.Convert(doc);

        if (!Directory.Exists(directory))
        {
            Directory.CreateDirectory(directory);
        }

        using (FileStream stream = new FileStream($"{directory}\\{fileName}", FileMode.Create))
        {
            stream.Write(pdf, 0, pdf.Length);
        }
    }

    private static void Converter_Error(object sender, DinkToPdf.EventDefinitions.ErrorArgs e)
    {
        Console.WriteLine("[ERROR] {0}", e.Message);
    }

    private static void Converter_Warning(object sender, DinkToPdf.EventDefinitions.WarningArgs e)
    {
        Console.WriteLine("[WARN] {0}", e.Message);
    }

    private static void Converter_Finished(object sender, DinkToPdf.EventDefinitions.FinishedArgs e)
    {
        Console.WriteLine("Conversion {0} ", e.Success ? "successful" : "unsucessful");
    }

    private static void Converter_ProgressChanged(object sender, DinkToPdf.EventDefinitions.ProgressChangedArgs e)
    {
        Console.WriteLine("Progress changed {0}", e.Description);
    }

    private static void Converter_PhaseChanged(object sender, DinkToPdf.EventDefinitions.PhaseChangedArgs e)
    {
        Console.WriteLine("Phase changed {0} - {1}", e.CurrentPhase, e.Description);
    }
}

System.AccessViolationException: 'Attempted to read or write protected memory. This is often an indication that other memory is corrupt.'

Since this is an Exception generating from an Unmanaged dll, I can't catch it.

I tried adding

GC.Collect();
GC.WaitForPendingFinalizers();

during every loop but it's not working. I'm fully aware that this error is fatal and not good to continue but I don't have a way to process 2000 files.

Is there any other way to either

1. Suppress the Exception and continue loop
2. Resolve this error by running it in a different app domain or something?

Answer 1

After a lot of trial and error I was able to make it work with a different way.

My intention is to run in 2000 times. My issue was when I put it inside the loop, I'm getting native exceptions

To make it work for my need

1. I removed the loop and generate PDF only for a single file. This file name I receive in a commandline argument

2. Then I created another console app that got a 2000 iteration loop and it'll call the main app as a Process.Start(); I can pass the filename as arguments

This way I managed to make for any number of iterations for time being. Since each process got different PID now Memory issue is not there