runtime: [hot reload] Could not parse field signature 0a0008a9 due to: Could not resolve type with token 010001f3 from typeref

Is there an existing issue for this?

I have searched the existing issues

Describe the bug

When I make a small change in my blazor wasm app, say just a minor change to the class attribute of an html element, dotnet watch fails and I get a series of exceptions like that shown below.

I’d at least appreciate some pointers on how to understand the exception and find the cause myself.

Expected Behavior

I’d expect the simple change to the class attribute to not result in an exception and to instead result in a quick change of the DOM in the web browser page.

At the very least I’d hope that the exception provides me with some information to help find the cause of the problem.

Steps To Reproduce

No response

Exceptions (if any)

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
    Unhandled exception rendering component: Field not found: Microsoft.AspNetCore.Components.EventCallback.0_10 Due to: Could not parse field signature 0a0008a9 due to: Could not resolve type with token 010001f3 from typeref (expected class 'Microsoft.AspNetCore.Components.<Main>$' in assembly 'Microsoft.AspNetCore.Components, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60') assembly:Microsoft.AspNetCore.Components, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60 type:Microsoft.AspNetCore.Components.<Main>$ member:(null)
    System.MissingFieldException: Field not found: Microsoft.AspNetCore.Components.EventCallback.0_10 Due to: Could not parse field signature 0a0008a9 due to: Could not resolve type with token 010001f3 from typeref (expected class 'Microsoft.AspNetCore.Components.<Main>$' in assembly 'Microsoft.AspNetCore.Components, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60') assembly:Microsoft.AspNetCore.Components, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60 type:Microsoft.AspNetCore.Components.<Main>$ member:(null)
    at Fusion.Client.Pages.Browse.Components.DocumentViewer.DocumentNavigator.BuildRenderTree(RenderTreeBuilder __builder)
    at Microsoft.AspNetCore.Components.ComponentBase.<.ctor>b__6_0(RenderTreeBuilder builder)
    at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)

.NET Version

7.0.304

Anything else?

Developing in latest Rider on the latest MacOS.

About this issue

Original URL
State: open
Created a year ago
Comments: 21 (12 by maintainers)

Most upvoted comments

An update… since deleting the bin and obj folders I cannot recreate the issue…

I will post an update if it returns but unfortunately atm I’m now unable to recreate

Drammy on Oct 18, 2023

Downloaded the link you posted

Unzipped it and placed into ~/.nuget/packages/microsoft.netcore.app.runtime.mono.browser-wasm/7.0.11, whilst removing the existing microsoft.netcore.app.runtime.mono.browser-wasm.7.0.11.nupkg file

Any ideas what I might be doing wrong?

@Drammy sorry. github doesn’t allow me to just upload a .nupkg file, so it had to be inside a zip.

What I meant is to do this:

unzip the .zip file and take the .nupkg file that is in there and put it somewhere.
unzip the .nupkg file itself so that it overwrites the contents of ~/.nuget/packages/microsoft.netcore.app.runtime.mono.browser-wasm/7.0.11

in particular the dotnet.wasm and dotnet.js files inside the .nupkg should overwrite the ones in ~/.nuget/packages/microsoft.netcore.app.runtime.mono.browser-wasm/7.0.11/runtimes/browser-wasm/native/

lambdageek on Oct 12, 2023

@drammy thanks for the update. This gives me enough to try some things for now. Enjoy your time off.

lambdageek on Aug 17, 2023

@Drammy thanks for the info. Can you show me a razor snippet that doesn’t reload properly? It doesn’t have to be self-contained, but if you’re using razor components, I’d like to see all the parent elements in the razor markup. If you’re using components that have ChildContent or some templated components, that is probably relevant.

@lambdageek It’s not one specific razor file; I can open any razor file and make a minor change to cause the issue.

Sometimes I get a different exception after making a change to the markup. we do not support patching of existing PARAM table cols

This can happen just by changing the html of MainLayout.razor, for example adding a space at the end of the class attribute value in the outer-most div of the blazor app…

I’m afraid I’m on annual leave atm and won’t be back until early September. I can try and provide some more details as soon as I’m back from my travels.

Drammy on Aug 17, 2023