Odd WeakReferenceMessenger error

[CADTraveller]

I have been using WeakReferenceMessenger service to communicate between ViewModels. I have nested structure, there is a 'Parent' ViewModel which contains 'Child' ViewModels and I want to get notice of state changes in 'Child' VMs.

In the Parent constructor i register as a receiver:

WeakReferenceMessenger.Default.Register<StatusUpdateEventArgs>(this, (r, m) =>
            {
                StatusMessage = m.Message;
            });

In the nested Child VM I will publish a message:

private void publishStatus(string message)
        {
            WeakReferenceMessenger.Default.Send(new StatusUpdateEventArgs(message));
        }

This works as expected in a test Harness project on my machine.

However, when a colleague runs this we are getting this error when sending the message:

Method not found: 'Boolean System.Runtime.CompilerServices.Unsafe.IsNullRef(!!0 ByRef)

Anyone recognize this? Since I cannot duplicate on my machine I'm struggling to investigate.

[Sergio0694]

That doesn't look right. What NuGet version are you using? What TFM are you using? Are you using .NET 7 preview by any chance? 🤔

[CADTraveller]

We do plugins/extensions for AutoCAD and Revit. I double my colleague even knows what Mono is.

Others in the company get the same error, it seems to only work correctly on my machine.

[CADTraveller]

I confirmed that we are only running MS .Net runtime.
Could it be related to SDK versions?

[Sergio0694]

I suspect it might, as I don't really see how this could be an issue in the MVVM Toolkit.
That said, I'm not really sure what could be causing it, and I can't repro this on my end either 🤔
Can you try running dotnet --list-sdks on your machine and your colleague's to see if there's any differences?
Also, are you both using the same VS version? Are you on the same OS version?

[CADTraveller]

I have:
3.1.421 [C:\Program Files\dotnet\sdk]
6.0.202 [C:\Program Files\dotnet\sdk]
6.0.203 [C:\Program Files\dotnet\sdk]
6.0.302 [C:\Program Files\dotnet\sdk]
6.0.400-preview.22330.6 [C:\Program Files\dotnet\sdk]
I'm running VS 17.3 Preview 3

Problem machine lists:
3.1.421 [C:\Program Files\dotnet\sdk]
6.0.301 [C:\Program Files\dotnet\sdk]
6.0.302 [C:\Program Files\dotnet\sdk]
Running VS 17.2.5

Both on latest public release of Windows 11

It's tough to see how the VS version would matter, as I had other colleagues get this same error after pulling down the .dll from our TeamCity buildserver.

[CADTraveller]

@Sergio0694 I might have finally discovered the cause of this issue. This came up again recently, my project works fine in VS and on my machine but fails with this same error in production. A colleague pointed out that it's likely the dependencies are different in the 2 environments, so I spent some time swapping .dlls until I found one which would trigger this error.

The version on the left is on my machine, and it sends messages just fine. The version on the right is from our published release, where the error occurs.

I'm not 100% on this just yet, I still need to update our release and make sure this resolves the issue. That has to be done by our TC admin so there's a bit of a delay.

But it sure looks like this is the culprit.

[ValeriyLappo]

I'm also encountered with this problem. using nuget package 8.3.2, but still when using WeakReferenceMessenger.Send() method it throws exception with message

Could not load file or assembly 'System.Runtime.CompilerServices.Unsafe, Version=4.0.4.1, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

For more information. If I install RevitPython shell with System.Runtime.CompilerServices.Unsafe.dll version of 4.6.28619.1 and it loads in Revit before my plugin, everything works fine. But if i delete it — got this exception

[Sergio0694]

You got some kind of assembly reference mismatch. Try adding an explicit package reference to System.Runtime.CompilerServices.Unsafe in your project with the right version. This sometimes happens on older frameworks in some corner case scenarios involving weird transitive dependencies using either packages.config or legacy-style .csproj projects.

[ValeriyLappo]

The problem is that i can't do it because i have a lot of other packages with that assembly, including MvvmToolkit. So my VS can't do it. Here an example from output

NU1605: Warning As Error: Detected package downgrade: System.Runtime.CompilerServices.Unsafe from 6.0.0 to 4.5.3. Reference the package directly from the project to select a different version.
MyProject -> CommunityToolkit.Mvvm 8.3.2 -> System.Runtime.CompilerServices.Unsafe (>= 6.0.0)
MyProject -> System.Runtime.CompilerServices.Unsafe (>= 4.5.3)