How can I avoid TaskCanceledException by RemoteNavigationManager

David Thielen 3,116

Hi all;

I have a Blazor server app and every couple of minutes I get the following in my logs:

Error 12:09:54 [] Microsoft.AspNetCore.Components.Server.Circuits.RemoteNavigationManager - Navigation failed when changing the location to https://louishowe-dev.azurewebsites.net/Identity/Account/Login TaskCanceledException: A task was canceled.
   at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](Int64 targetInstanceId, String identifier, Object[] args)
   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)
   at Microsoft.AspNetCore.Components.Server.Circuits.RemoteNavigationManager.<>c__DisplayClass13_0.<<NavigateToCore>g__PerformNavigationAsync|0>d.MoveNext()
Error 12:09:54 [] Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost - Unhandled exception in circuit 'GdWjUPhwt9bdljJjyKo0M-eVaVKtacUkhqCtNuwOg-s'. TaskCanceledException: A task was canceled.
   at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](Int64 targetInstanceId, String identifier, Object[] args)
   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)
   at Microsoft.AspNetCore.Components.Server.Circuits.RemoteNavigationManager.<>c__DisplayClass13_0.<<NavigateToCore>g__PerformNavigationAsync|0>d.MoveNext()

The program continues to run fine and the user sees no issue. But exceptions are generally bad news. What's going on here and how do I avoid this?

thanks - dave

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JasonPan - MSFT 5,466 Reputation points Microsoft Vendor

2024-03-11T01:53:25.5033333+00:00

Hello @David Thielen,

From the error message, it seems code issue in your project.

Could you create a sample project that can reproduce the problem for us ? And make sure there is no any sensitive information or business code in it. We will help you investigate this issue.

Best Regards

Jason
David Thielen 3,116 Reputation points

2024-03-11T16:59:22.6733333+00:00

@JasonPan - MSFT Unfortunately all my simple apps don't have this problem. And it's rare in my application that is getting this.

Any suggestions on how I can go about figuring out what in my code is a problem?

thanks - dave
JasonPan - MSFT 5,466 Reputation points Microsoft Vendor

2024-03-12T04:25:49.2533333+00:00

Dear @David Thielen,

Maybe you can choose to streamline your current project and remove business-related code and confidential information?

Best Regards

Jason
David Thielen 3,116 Reputation points

2024-03-12T11:51:38.7833333+00:00

@JasonPan - MSFT This happens maybe once or twice a day. So to follow your suggestion I would have to strip something out, then have 2 QA people use that stripped out version for several hours, then strip some more and repeat.

That's not something we can afford. In fact, I'm not sure Microsoft could afford that approach.

How can I figure out the problem without stripping the app down?

thanks - dave
JasonPan - MSFT 5,466 Reputation points Microsoft Vendor

2024-03-13T01:48:25.8566667+00:00

Hi @David Thielen,

Now that you have Debug logging enabled, there is no good way to fix this unreproducible problem.

Maybe we can try to write a custom middleware to capture the TaskCanceledException.

Best Regards

Jason

6 answers

Bruce (SqlWork.com) 65,131 Reputation points

2024-05-15T21:03:37.3766667+00:00

Your issue is that remote navigation, redirects the browser to a new page. in prep a clean Blazor shutdown is attempted. it needs to close the signal/r connection, and unload the Blazor app instance. this requires all threads exit, typically via a cancellation token. any dangling threads need to be killed.

in your case Blazor is redirecting to login. beside there a minimum side effects when this happens.
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How can I avoid TaskCanceledException by RemoteNavigationManager

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