TypeLoadException at MagickImageCollection.AddImages with Mono on Ubuntu

Hey,

I’m currently trying to convert pdf files using Magick.NET with Mono on Ubuntu 16.04. However, when executing this simple console application:

public static class Program
{
    public static void Main()
    {
        using (var images = new MagickImageCollection())
        {
            images.Read("Snakeware.pdf");
            for (var i = 1; i <= images.Count; i++)
            {
                images[i].Write($"Snakeware.Page.{i}.png");
            }
        }
    }
}

I get the following exception:

/usr/bin/mono /home/pettfre/Repos/typeloadexception-magicknet/Magick.Net.Error/ConsoleApplication/bin/Debug/ConsoleApplication.exe
Could not load signature of ImageMagick.MagickImage:ToBitmapSource due to: Could not load file or assembly 'PresentationCore, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. assembly:PresentationCore, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 type:<unknown type> member:<none>
Could not load signature of ImageMagick.IMagickImage:ToBitmapSource due to: Could not load file or assembly 'PresentationCore, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. assembly:PresentationCore, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 type:<unknown type> member:<none>

Unhandled Exception:
System.TypeLoadException: Could not resolve the signature of a virtual method
  at ImageMagick.MagickImageCollection.AddImages (System.IntPtr result, ImageMagick.MagickSettings settings) [0x00007] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.AddImages (System.String fileName, ImageMagick.MagickReadSettings readSettings, System.Boolean ping) [0x00034] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.Read (System.String fileName, ImageMagick.MagickReadSettings readSettings) [0x00006] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.Read (System.String fileName) [0x00000] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ConsoleApplication.Program.Main () [0x00008] in <c949cae22a174c79a3837c6587272ad8>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.TypeLoadException: Could not resolve the signature of a virtual method
  at ImageMagick.MagickImageCollection.AddImages (System.IntPtr result, ImageMagick.MagickSettings settings) [0x00007] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.AddImages (System.String fileName, ImageMagick.MagickReadSettings readSettings, System.Boolean ping) [0x00034] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.Read (System.String fileName, ImageMagick.MagickReadSettings readSettings) [0x00006] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ImageMagick.MagickImageCollection.Read (System.String fileName) [0x00000] in <45292dcb447e4450bb12f45cb1a5f855>:0 
  at ConsoleApplication.Program.Main () [0x00008] in <c949cae22a174c79a3837c6587272ad8>:0 

I have renamed the Magick.NET-Q8-x64.Native.dll.so to libMagick.NET-Q8-x64.Native.dll.so and am clueless as to what I am supposed to do in order to solve this problem.

Is this a problem in the library or in my setup?

[pettfre]

Okay, so what I ended up doing was a post build step:

<Target Name="AfterBuild">
  <Copy SourceFiles="..\packages\Magick.NET-Q8-x64\lib\netstandard13\Magick.NET-Q8-x64.dll"
        DestinationFolder="$(TargetDir)">
  </Copy>
</Target>

This makes sure that the net40 version is replaced with netstandard13 version before (in my case) tests are executed.

Thanks a lot for your help!

[dlemstra]

Thanks for coming back and explaining how you solved this 👍