.NET 6.0 - TypeLoadException

[danielgindi]

Type of issue

[X] Bug
[ ] Question (e.g. about handling/usage)
[ ] Request for new feature/improvement

Expected Behavior

Should load the assembly.

Current Behavior

Referencing the library throws a TypeLoadException, with zero information.
This happens when targeting .NET 6.0, and the actual dll copied to the bin folder is that of the .NET 6.0 (~120KB).
When overwriting with the .NET Standard dll, or the .NET 5.0 dll - it works.

Possible Solution (optional)

Recompile?

Steps to Reproduce (for bugs)

1. New project
2. Target .NET 6.0
3. Reference QRCoder 1.4.3
4. Reference any class from the library

Your Environment

• Version used: 1.4.3
• Compiled from source or NuGet package?: NuGet
• Payload/Encoded text:
• Used payload generator:
• Used ECC-level:
• Used renderer class:
• Environment (.NET 3.5, .NET 4.X, .NETCore, ...): .NET 6.0
  -->

[Anduin2017]

Same here.

[TruffleMuffin]

Same here

[onatsko]

Same here

[onatsko]

all works fine with version Include="QRCoder" Version="1.4.1"

[pauledrupt]

same here

[Darkfeast]

all works fine with version Include="QRCoder" Version="1.4.1"

thanks , I can't find class QRCode in 1.4.3 , 1.4.1 is fine!

[hakimben13000]

Error : cs0246 : namespace 'QRCode' not found

[d-barker]

I have the same or similar issue,

I am on a cross platform build, local macos and remote alpine linux container. We are in the process of upgrading from 3.1 to net6.0. And we came across this issue.

My error is as follows:

System.TypeLoadException : Could not load type 'ImageType' from assembly 'QRCoder, Version=1.4.3.0, Culture=neutral, PublicKeyToken=c4ed5b9ae8358a28'.

Rolling back to 1.4.1 does not help my case, as I get a new exception throwing,

Failed to create QR Code due to error: The type initializer for 'Gdip' threw an exception. System.TypeInitializationException: The type initializer for 'Gdip' threw an exception.
 ---> System.PlatformNotSupportedException: System.Drawing.Common is not supported on non-Windows platforms. See https://aka.ms/systemdrawingnonwindows for more information.

dotnet 6.0 removes support for the System.Drawing.Common only supported on Windows:
https://docs.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/6.0/system-drawing-common-windows-only

Looks like the base64 encoder will need to find a cross platform alternative, PR anyone?

• ImageSharp
• SkiaSharp
• Microsoft.Maui.Graphics

[aguarino77]

Same here while upgrading to net6...

[adbdehghan]

Same here while upgrading to net6...

[Anduin2017]

Is this project still being maintained? Now the basic demo in the home readme can produce this issue. Please fix this.

[abhith]

Do we have any alternatives to this library that works in .net6?
Because of this issue, our project migration from .net5 to .net6 is blocked and we are almost close to .net7, so can't wait more 😔.

[danielgindi]

You can enable System.Drawing for .NET 6. It's disabled by default because some features are not available cross-platform, but this library does not use any of those.

[willshoemaker]

There are conditional compilation symbols in the QRCode class
#if NETFRAMEWORK || NETSTANDARD2_0 || NET5_0 || NET6_0_WINDOWS
The NET6_0_WINDOWS part is the problem. It is causing that class to not be compiled into the normal net6.0 package, which is the one that visual studio pulls in when compiling if your target framework is net6.0

If you explicitly load the library from the netstandard2.0 folder instead the library works. You can technically even just replace the .dll in the output directory with the one from the netstandard2.0 folder. I would guess setting your target framework to net6.0-windows would also work.

I don't know if this is because of a compatibility issue with some dependency or just an oversight. But it's essentially making the net6.0 version of the library match the netstandard1.3 version of the library - which doesn't have the QRCode class.

I'd guess the compilation symbol should be NET5_0_OR_GREATER, but again I don't know if this was intentional or not.

[rdhainaut]

@willshoemaker thanks for your comment

You can set option of your project to run on 'Windows' target
Right clic on your project -> properties -> Application/General/TargetOs [Windows]