Server side Blazor components in MVC and Razor pages can fail silently during Component Initialisation

When running a Blazor app in a project created with the server side Blazor (SSB) template, errors of the following nature will all cause the gold error bar to be shown when a component is being loaded:

• When a dependency registration is missing for a service injected into that component
• When an error occurs in the constructor for of a service injected into a component
• When the component’s OnInitialized method calls a method in a service that then throws an error

If I then add an MVC project to the solution, set it up as per my notes here, and then place those same components on MVC pages in that new MVC project, the error behaviour seems to be different:

Missing dependency registrations and injected services constructor errors

Component fails completely silently:

• No gold bar
• No logging entries at all, not even at Debug level

Errors from OnInitialized and onwards in the lifecycle

Component fails visibly:

• Gold bar shown
• Logging entry at the ‘Warn’ level

I’ve also had times where a Debug level log entry has been added (as per case #17508) but no gold bar is shown, however I can’t reproduce that in the repo below.

It’s very possible that I’m configuring the MVC project incorrectly in some way to use the components from the Blazor project, but in all other respects this seems to be working well in our app which is in final production testing with a client at the moment.

To Reproduce

I’ve created a repo here: https://github.com/tomRedox/BlazorInMvcFailsSilently

It has two projects, a Blazor project and an MVC project.

There are three services, components and MVC pages, one for each type of error.

If you set the start up app to the Blazor project, you’ll see gold error bars for all the different components, whereas if you set the startup project to MVC you’ll only get the gold error bar on the Method Error page.

Further technical details

• ASP.NET Core version:
  Core 3.1 Preview 3

• Include the output of dotnet --info .NET Core SDK (reflecting any global.json): Version: 3.1.100-preview3-014645 Commit: b32d27f4b3

Runtime Environment: OS Name: Windows OS Version: 10.0.17763 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\3.1.100-preview3-014645\

Host (useful for support): Version: 3.1.0-preview3.19553.2 Commit: 13f35c3d86

.NET Core SDKs installed: 2.1.201 [C:\Program Files\dotnet\sdk] 2.1.202 [C:\Program Files\dotnet\sdk] 2.1.402 [C:\Program Files\dotnet\sdk] 2.1.500 [C:\Program Files\dotnet\sdk] 2.1.507 [C:\Program Files\dotnet\sdk] 2.1.508 [C:\Program Files\dotnet\sdk] 2.1.509 [C:\Program Files\dotnet\sdk] 2.1.602 [C:\Program Files\dotnet\sdk] 2.1.700-preview-009601 [C:\Program Files\dotnet\sdk] 2.1.700-preview-009618 [C:\Program Files\dotnet\sdk] 2.1.800-preview-009696 [C:\Program Files\dotnet\sdk] 2.2.202 [C:\Program Files\dotnet\sdk] 3.0.100-preview7-012821 [C:\Program Files\dotnet\sdk] 3.0.100-preview8-013656 [C:\Program Files\dotnet\sdk] 3.0.100-preview9-014004 [C:\Program Files\dotnet\sdk] 3.0.100 [C:\Program Files\dotnet\sdk] 3.1.100-preview2-014569 [C:\Program Files\dotnet\sdk] 3.1.100-preview3-014645 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed: Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.0.0-preview8.19405.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.0.0-preview9.19424.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.0-preview2.19528.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.0-preview3.19555.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.0.0-preview9-19423-09 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.0-preview2.19525.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.0-preview3.19553.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.0.0-preview9-19423-09 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.1.0-preview2.19525.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.1.0-preview3.19553.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE (VS / VS Code/ VS4Mac) you’re running on, and it’s version Microsoft Visual Studio Professional 2019 Preview Version 16.4.0 Preview 4.0

[ryanbrandenburg]

@tomRedox we have automation that’s supposed to do this when the Author replies so that it’s faster and more reliable, but apparently that’s not working ATM.

[mkArtakMSFT]

This should be fixed now. Please use the upcoming 3.2-preview2 release to validate.