.NET 6.0 Compilation Error: The type or namespace name 'QRCode' does not exist in the namespace 'QRCoder'

[Illeris]

Type of issue

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

Expected Behavior

.NET 5.0 project with QRCoder assembly reference compiles without error.
.NET 6.0 project with QRCoder assembly reference does not compile : The type or namespace name 'QRCode' does not exist in the namespace 'QRCoder'

Current Behavior

Possible Solution (optional)

Steps to Reproduce (for bugs)

• Include library in .NET 5.0 assembly project
• Include QRCoder (sth like this):
  QRCoder.QRCodeGenerator qrGenerator = new QRCoder.QRCodeGenerator();
  QRCoder.QRCodeData qrCodeData = qrGenerator.CreateQrCode(payloadMessage, eccLevel);
  QRCoder.QRCode qrCode = new QRCoder.QRCode(qrCodeData);
• Compile : will work
• Switch target of project to .NET 6.0 : error

Compilation: VS2022

Your Environment

[danielhw2]

Same problem here...

[MarkNorman]

Also seeing this.

[WatchDogsDev]

Also here. Any solution for this ?

[joseph-passineau]

Here is the explanation and some possible solutions:
#361 (comment)

[chrpai]

I'm new here but my experience was like this....

I need to create a program to generate some QR codes. Ok new console app and take default of .net 6.
Open nuget... this was has 8M downloads lets give it a try. Go to the project and find the 5 line sample and paste it in.
Hmmm that's strange this type isn't recognized.
Go to issues page and find this issue. Switch to target windows only and not it compiles.

So I'd that a notation be placed in the README.md for newcomers like myself.

[wensaint]

roll back to 1.4.1, then the error gone.

[akosilataunglahat]

roll back to 1.4.1, then the error gone.

This works for me. Thank you @wensaint .. :)

[lvlvlvlvlvlv]

QRCode qrcode = new QRCode(codeData); ?????

[PeterHric]

QRCode qrcode = new QRCode(codeData); ?????

Actually no - I had to take it back..
Apparently I solved it other way.. Dunno how :)

[simonpinn]

Same issue #435

[ruggedwizard]

rollback to version 1.4.1, this fixes the QRCode issues on Dotnet 6.0 and also 7.0

[SeniorKian]

ruggedwizard

thank you ...

[KC7465128305]

I found the problem.

Go to the project properties, in the Target OS, specify it to Windows. Rebuild the solution. Problem solved.

[jainam33]

Just switch to Nuget package manager version 1.4.1
first uninstall latest version of QRCoder then install 1.4.1

[Michael-Bohin]

This issue is existing still in 2025. I have managed to fix the issue by setting solution properties - target OS -> Windows. However this fix will only work for me for local development as I will need to deploy on Linux.

Is there a solution once I will try to build the code for Linux?

I have read through the mention #512

@codebude My best understanding at this point, is that if I want to be multiplatform, I should use the BitmapByteQRCode renderer class, correct? (With QRCode being only available if I specifically set target OS to Windows in VS solution properties)

Also as a unasked-for-feedback, I have run into your library via GPT research recommendation. I think there are likely going to be more users coming from this channel in the future. The information that I cant use the main renderer if I want to compile, but should use the BitmapByteQRCode is quite too deep in the docs. What would help me personally is some specific mention in third pargraph here
https://github.com/codebude/QRCoder/wiki

saying something like in bold font:

If you want to use the QRCode render and are OK being Windows only, set solution - properties - target OS -> Windows

If you need to be multiplatform, dont use QRCode render, but x, y renderer.

I bet this docs change will decrease potential lib users bounces in the future.