There was no runtime pack for Microsoft.AspNetCore.App available for the specified RuntimeIdentifier 'browser-wasm'

Question

Trying to migrate from ASP.NET Core 3.1 to 5.0 using this guide provided by Microsoft.

Installed SDK 5.0.100-rc.1 with runtimes. Updated project as guide says and sti

Answer 1

Thanks for your help, In my case, I have to followup steps mentioned by @Kasta and official guide.

I make sure that below SDK changes are in place,Thank you @OzanYasinDogan for mentioning this helps.

• Client - Microsoft.NET.Sdk.BlazorWebAssembly
• Server - Microsoft.NET.Sdk.Web
• Shared - Microsoft.NET.Sdk

In my case, I had to

• Remove the <RuntimeIdentifier>browser-wasm</RuntimeIdentifier> and <UseBlazorWebAssembly>true</UseBlazorWebAssembly>. Mentioned here
• Remove Microsoft.AspNetCore.Components.WebAssembly.BuildServer which was version 3.xx.xx causing conflicts from Blazor.Client Project file.

Answer 2

I resolved this issue in a way Richard described:

1. Cleaned up references to Microsoft.Extensions.Logging, Microsoft.Extensions.Configuration,... packages version 3.2 in all solution projects referenced by server and client
2. Updated .Server project
3. Updated .Client project. Kept element at target framework section and it worked

<PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <RazorLangVersion>3.0</RazorLangVersion>
</PropertyGroup>

Answer 3

Had the same issue and finally got it working. Here's how.

In my case, the error wasn't the result of the Blazor project itself, but a referenced project in the same solution. The referenced project targets .net standard 2.1, which should be fine in itself; however, it also had some NuGet packages installed which might conflict with Blazor dependencies: (Microsoft.Extensions.*).

Solution
- Project A (.net standard 2.1 - Class library)
  - Dependencies
    - Packages
      - Microsoft.Extensions.Configuration.Json (<-- example dependency)
- Project B (.net 5 - Blazor webassembly)
  - Dependencies
    - Projects
      - Project A (<-- caused the error, presumably because of the above dependency)

The blog post about .net 5 rc mentions all Microsoft.Extensions.* packages in a Blazor project should be updated to 5.0.0-rc.1.*.

Was able to resolve the issue by removing the project dependency (which I didn't need in the first place, but accidentally got placed there).

What I don't understand is why a 'dotnet build' doesn't give an understandable error message about a conflict instead of this vague message about the runtime identifier mentioning the Blazor project.

Hope this will help others as well.

Answer 4

I finally made it work.

I did everything that guide said, except for the project file which I changed to this:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <UserSecretsId>*****</UserSecretsId>
    <UseBlazorWebAssembly>true</UseBlazorWebAssembly>
  </PropertyGroup>
...

But I have no idea if it is correct when official upgrade guide says to use:

<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">

instead of:

<Project Sdk="Microsoft.NET.Sdk.Web">

Answer 5

I faced the same issue and asked Microsoft about that under this post: https://github.com/dotnet/aspnetcore/issues/27738

You need to update your projects to use below SDK's;

Client - Microsoft.NET.Sdk.BlazorWebAssembly
Server - Microsoft.NET.Sdk.Web
Shared - Microsoft.NET.Sdk

Answer 6

I had this issue with a different error message "The type or namespace name 'ApplicationPartAttribute' does not exist in the namespace 'Microsoft.AspNetCore.Mvc.ApplicationParts' (are you missing an assembly reference?)".

In my case I had a shared helper class library that I had started to build generic data api repositories into using Microsoft.AspNetCore.Mvc 2.0 which was referenced in my Blazor project using the newly released .Net 5.

To resolve this, I had to separate the shared class project moving the generic data api elements to a new project which removed the link between .Net 5 Blazor and Microsoft.AspNetCore.Mvc 2.0.