Can't debug wasm project after update to VS 17.8.6

[appel1]

Describe the bug

When attempting to debug a browser showing about:blank appears and then goes away after a while and an error is shown in VS.

Seems like a VS issue but thought I should mention it here in case there's a known solution or workaround.

See https://developercommunity.visualstudio.com/t/Debug-of-Avalonia-WebAssembly-app-fails-/10576821

To Reproduce

Create a new avalonia xplay solution using sorbet new avalonia.xplat
Debug browser peojwct

Expected behavior

Successful debug as with 17.8.4

Environment

• OS: Windows 11
• Avalonia-Version: 11.0.7
• Same with both Edges and Chrome

[migubis]

We have observed a similar problem and found out that it is (in our case) connected with the usage of UseUrls. I have submitted it to Microsoft under
https://developercommunity.visualstudio.com/t/Debugging-does-not-work-when-UseUrls-is/10582270

My problem is not connected to Avalonia in any way, but I thought maybe it helps to share my findings.

[maxkatz6]

I will convert this issue to discussion, as it has a very chance of being caused by Avalonia.
But there still could be some workaround or useful links to share.

[mb-jp]

Any news on this? it's a big problem for me 😭

[maxkatz6]

You might try .NET 9 previews with preview Visual Studio.
I haven't tested, but if it was fixed in runtime, it should be available there.

[mb-jp]

I couldn't get it to work with .NET 9 previews and preview Visual Studio. 😟

[JW-CH]

Any update on this?

[DVaughan]

Today I updated VS to Version 17.10.0 Preview 7.0. The problem still persists. I realize this may be a VS issue, but would like to know if there is a work-around that someone is aware of to get the stock Avalonia web template to launch and attach to the browser. Some things I've tried that have not worked:

• Modified await dotnetRuntime.runMainAndExit to runMain
• Tried alternate URLs in launchSettings.json: "applicationUrl": "https://localhost:5001;http://localhost:5000",
• Changed csproj file TargetFramework from net7.0 to net8.0 (I had an issue with updating the webassembly workload unfortunately).

[yll690]

You can try the 360 browser: https://browser.360.cn/eex/index.html . My Edge and Chrome open the about:blank but the 360 browser can open https://localhost:5001/index.html

Or use IIS Express configuaration.

[JW-CH]

Still not resolved for me.

[anispider]

Same here. Luckily, my code runs on multiple platforms, so I use those to debug, otherwise this would be a show-stopper. It does seem like a VS bug, since it seemed to manifest immediately after the upgrade mentioned in the OP title, but then again brand new Blazor WASM projects debug just fine.

If anyone on the team would like end user assistance on this, I'd love to help. Even if it is a VS bug, it seems to have a big impact on Avalonia development. I haven't tried Uno in a while, but back when this issue first appeared, Uno debugging was broken too.

[timunie]

@anispider we can offer this to users who have paid support. If you have a support agreement, reach out to the team.

[anispider]

@timunie I think you misunderstood me, I wasn't asking for help, I was offering it. This issue does impact me, but I can work around it in my scenario, as inconvenient as that may be. But whether or not the root cause lies with VS or Avalonia (I suspect it is VS), I would think the Avalonia team would have a lot of interest in getting it resolved, since it kind of takes away from one of Avalonia's key strengths, being able to share code between the browser and other platforms, and debugging code running in-browser.

I really love the framework you have built, and want to see it grow in adoption, but if I knew nothing about it, and I was tasked in a corporate job with evaluating tech stacks for a new project, the broken debugging thing might lead me to blame the issue on Avalonia and conclude that it wasn't mature yet.

[WAASSTT]

Can this problem be solved in VS? Because I've been having this issue recently as well

[anispider]

@WAASSTT I feel like this issue is pretty close to being solved. I'm not sure what has changed recently, but in VS 17.11.1 (the latest stable version as of the time of this comment), and with a brand new browser project using Avalonia 11.1.X I can at least launch in the debugger. Breakpoints don't seem to work, but it's a slight improvement from where this issue was a few months ago. My existing Avalonia projects still seem broken, so maybe there is some legacy cruft in my project files or launch settings that it doesn't like.

[anispider]

(And bringing my "legacy" projects up to Avalonia 11.1.3 didn't fix them, so whatever change allowed brand new projects to almost work, I think it was something in the Avalonia new project wizard templates)