Aspnetcore: DotNet.invokeMethodAsync faild when invoke Task<T> method on c# code

[danielmeza]

When I try to call a async generic method from JavaScript I get this error: The assembly '{assemblyName}' does not contain a public method with [{nameof(JSInvokableAttribute)}("{methodIdentifier}")].
[JSInvokable] public static Task<string> GetAccessToken(string connectionId)
its related to ScanAssemblyForCallableMethods in https://github.com/aspnet/Blazor/blob/master/src/Microsoft.JSInterop/DotNetDispatcher.cs

It's a missing feature on this implementation?
And if it's, is someone working on implementing?

[danroth27]

Hmm, well that error message seems a bit broken.

What values did you actually pass to the invokeMethodAsync call from JavaScript for the assembly name and the method name?

[danielmeza]

@danroth27 I´m sorry, I copyed the error template from the source code. The error showme the "Blazor.Extensions.SignalR " as assmeblyName.
I'm triyng to migrate the SignalR extensions to the new JavaScript Interop spec. I can call others methods whitout problem and the diference bettwen then is Task, so i guess this can bew the cause
I'm also clone the Blazor repo and I will test on my machine to see what is happen whit this issue.

[danroth27]

@danielmeza Could you please share the JavaScript code you are using to call the async .NET method that is failing?

[danroth27]

Calling async methods that return Task should be fine. We have test cases that cover this: https://github.com/aspnet/Blazor/blob/master/test/testapps/BasicTestApp/wwwroot/js/jsinteroptests.js#L58.

[danroth27]

@galvesribeiro FYI

[galvesribeiro]

Hey folks, thanks for ping me.

I’m doing the migration of all components right now. I hanged for a moment dealing with prototype collisions if you were using multiple BlazorExtension components in the same project due to the change/removal on the register method.

I just found a solution and will kee updating the packages. In an hour or so I expect the packages to be live.

Will keep you posted.

[danielmeza]

@galvesribeiro I solve the issue by changin the container class from internal to public so the refection not found the method if it´s Generic and if the container class is not public.

[danroth27]

@danielmeza I'm glad you solved your issue!