Exception: "Unable to find main thread"

[Chris-TritonAppworks]

I've created a new MAUI app project and added the DrawnUI.Maui package to the project. Now when I run it, I get the InvalidOperationException thrown by MainThread.PlatformBeginInvokeOnMainThread. I haven't been able to find any references to this behavior. Can anyone provide insight?
TIA

[taublast]

Hi just to make sure, what is the nuget version you added, and i suppuse we are talking about windows? .net9 or .net10?

[Chris-TritonAppworks]

Yes, Windows. Package is v1.7.4.1.

[taublast]

That's a very interesting issue that i'm failing to reproduce, just created a new project on purpose.. I was catching a similar issue before 1.7.4.1, but this one had to go away with this: 79d25d8.
As you would see here we have the mainthread invokation wrapped with try-catch and retry logic until main main thread become available:

DrawnUi/src/Maui/DrawnUi/Platforms/Windows/Super.Windows.cs

Line 120 in 9380e0d

if (MainThread.IsMainThread) //UI thread is available

If you could provide a repro project or more ideas that would be awesome.

[taublast]

@Chris-TritonAppworks Can i possibly ask you to test with a prerelease nuget version: 1.7.4.2-pre? Thanks!

[taublast]

I have also created another variation of startup with 1.7.4.3-pre would be cool if you could try them both to see if they manage to solve it.

[QrtAwb]

@taublast: Maybe this can help: because I had the same problem after updating from 1.7.2.2 to 1.7.4.1 I downloaded your source package. I could solve the problem in making the same modification to 'Looper.cs' as you already did in 'Super.Windows.cs' (see added modified Looper.cs, StartOnMainThread). I tested with the included samples 'Tutorials' and 'Sandbox'. The MainThread is found after 3-4 unsuccessful tries. (sorry - adding as 'cs' file was refused, why?)
looper.txt

[taublast]

@QrtAwb thanks! could you possibly try new preview nugets? :)))

[QrtAwb]

@taublast i tested both pre versions with the Samples/Tutorials project: compiling ok, but i got still 'unable to find main thread' when trying to run the project.

[taublast]

OMG. Thanks to your post about looper now i get why i couldn't reproduce: on my pc it was on path UsingDisplaySync being true and Looper.cs was never used, so i just didn't know that anyone could have issues with it!

[taublast]

@Chris-TritonAppworks @QrtAwb I think this is now fixed in the nuget 1.7.4.4 as i finally touched the Looper, thanks to you!

If someone could please confirm it fixed the issue, then we could merge and close this.

[Chris-TritonAppworks]

Confirmed fixed for me 😍🤘

[taublast]

nice! thank you very much to both of you for this feedback, without it i would still be sure that all works fine for everyone else!

[QrtAwb]

Confirmed fixed for me, too

[Chris-TritonAppworks]

So refreshing to see this kind of quick cooperation. Thank you both very much!