Scaffolding Minimal Api with a separate DbContext project throws error "Could not load information for ..."

Question

I have a solution name BugDemo consisting of 2 projects. Here is the github repo.

a class library named Data.
an Asp.Net Core Minimal Api named Api referencing Data project. I set Api project as the startup project.

I use User Secret to share secret.json between these 2 projects.

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=.;Database=BugDemoDb;Integrated Security=true;TrustServerCertificate=true"
  }
}

I successfully generated the database with the following (executed from solution directory):

dotnet ef migrations add Initialization --startup-project Data --project Data
dotnet ef database update --startup-project Data

I attempted to invoke scaffolding with the following:

$env:codegen_trace=1 
dotnet-aspnet-codegenerator minimalapi --project api

And I got the following errors:

Line: minimalapi --project api Trace: Executing external command: dotnet msbuild C:\Projects\BugDemo\api\Api.csproj /t:EvaluateProjectInfoForCodeGeneration /p:OutputFile=C:\Users\amd\AppData\Local\Temp\wybiwf1d.d4d;CodeGenerationTargetLocation=C:\Users\amd.dotnet\tools.store\dotnet-aspnet-codegenerator\7.0.0-rc.1.22452.2\dotnet-aspnet-codegenerator\7.0.0-rc.1.22452.2\tools\net7.0\any;Configuration=Debug -restore

Building project ... Trace: Executing external command: dotnet build C:\Projects\BugDemo\api\Api.csproj --configuration Debug --framework net7.0

Trace: Executing external command: dotnet exec --runtimeconfig C:\Projects\BugDemo\api\bin\Debug\net7.0\Api.runtimeconfig.json --depsfile C:\Projects\BugDemo\api\bin\Debug\net7.0\Api.deps.json C:\Users\amd.nuget\packages\microsoft.visualstudio.web.codegeneration.design\7.0.0-rc.1.22452.2\lib\net7.0\dotnet-aspnet-codegenerator-design.dll --no-dispatch --port-number 62322 minimalapi --project api --dispatcher-version 7.0.0-rc.1.22452.2

Trace: Command Line: --no-dispatch --port-number 62322 minimalapi --project api --dispatcher-version 7.0.0-rc.1.22452.2 Scaffolding failed. Could not load information for project ..\Data\Data.csproj Trace: at Microsoft.VisualStudio.Web.CodeGeneration.Utils.RoslynWorkspaceHelper.GetProjectReferenceInformation(IEnumerable1 projectReferenceStrings) at Microsoft.VisualStudio.Web.CodeGeneration.Utils.RoslynWorkspace..ctor(IProjectContext projectInformation, String configuration) at Microsoft.VisualStudio.Web.CodeGeneration.Design.CodeGenCommandExecutor.AddFrameworkServices(ServiceProvider serviceProvider, IProjectContext projectInformation) at Microsoft.VisualStudio.Web.CodeGeneration.Design.CodeGenCommandExecutor.Execute(Action1 simModeAction) at Microsoft.VisualStudio.Web.CodeGeneration.Design.Program.<>c__DisplayClass4_0.<b__0>d.MoveNext() RunTime 00:00:12.60

Project `Api`

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

  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <UserSecretsId>b3fdc987-781a-4fd4-853d-e279524cb5c6</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="7.0.0-rc.1.22427.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="7.0.0-rc.1.22426.7" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="7.0.0-rc.1.22426.7">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="7.0.0-rc.1.22452.2" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.4.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\Data\Data.csproj" />
  </ItemGroup>

</Project> 


using Data;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);


builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddDbContext<AppDbContext>(opts =>
{
    opts.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});
var app = builder.Build();


if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.MapGet("/", async (AppDbContext ctx) =>
{
    return await ctx.Students.ToListAsync();
});

app.Run();

Project `Data`

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

  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <UserSecretsId>b3fdc987-781a-4fd4-853d-e279524cb5c6</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="7.0.0-rc.1.22426.7">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="7.0.0-rc.1.22426.7" />
    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="7.0.0-rc.1.22426.10" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="7.0.0-rc.1.22452.2" />
  </ItemGroup>

</Project>


namespace Data;

public class Student
{
    public int Id { get; set; }
    public string Name { get; set; } = default!;
}


using Microsoft.EntityFrameworkCore;

namespace Data;

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> opts) : base(opts) { }
    public DbSet<Student> Students { get; set; }
    protected override void OnModelCreating(ModelBuilder mb)
    {
        base.OnModelCreating(mb);
        mb.Entity<Student>().HasData(new Student[]
        {
            new Student{ Id=1,Name="Albert Einstein"},
            new Student{ Id=2,Name="Isaac Newton"},
            new Student{ Id=3,Name="Blaise Pascal"},
            new Student{ Id=4,Name="Nicola Tesla"}
        });
    }
}



using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.Extensions.Configuration;

namespace Data;

public class AppDesignTimeDbContextFactory : IDesignTimeDbContextFactory<AppDbContext>
{
    public AppDbContext CreateDbContext(string[] args)
    {
        IConfiguration config = new ConfigurationBuilder()
             .AddUserSecrets<Data.AppDesignTimeDbContextFactory>()
             .Build();

        var opts = new DbContextOptionsBuilder<AppDbContext>();
        opts.UseSqlServer(config.GetConnectionString("DefaultConnection"));

        return new AppDbContext(opts.Options);
    }
}

Question

How to fix this issue?

First, from the [dotnet-aspnet-codegenerator](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/tools/dotnet-aspnet-codegenerator?view=aspnetcore-6.0) document, we can see this command doesn't have the minimalapi option, so the command will not work. Second, as you said, the Data project is the class library, it should provide the relates method to do the CRUD operation, then, in the API application, we can only add the Data project reference and call the relates method, instead of directly use the dbcontext to access the database. So, try to modify your code. — Zhi Lv, Sep 19 '22 at 06:16
I am fighting with the same issue. My project is .NET 6 Core MVC. My data is in a separate class library which is referenced as project. — Boris Todorov, Sep 29 '22 at 19:48
Downgrading the target framework from 7.0 to 6.0 solves the problem. — The Real Masochist, Oct 07 '22 at 23:48

score 1 · Answer 1 · answered Oct 04 '22 at 20:20

I've raised that to the project community. There is an issue with downgrading the version of the Microsoft.VisualStudio.Web.CodeGeneration.Design library during scaffolding. As I understand how the discussion ended - they assigned the issue to a developer and in future will be fixed(as I can see in next major version). You can follow the it in github.

The scaffolding project during the process of scaffolding updates the libraries of the projects and do a build behind the scene. And wrongly downgrading their own project version.

My workaround is to create a clean new project with pre-configured Identity, scaffolding what I need and copy the results to my project. Works perfect.

score 1 · Accepted Answer · answered Oct 07 '22 at 19:59

The issue is fixed in Visual Studio version - 17.3.4 and above. Currenly the latest one is 17.3.4 The problem was that during scaffolding the CodeGeneration library was downgraded from 6.0.10 to 6.0.9. With the fix it is not downgrading anymore and it works properly.

https://github.com/dotnet/Scaffolding/issues/2034

Scaffolding Minimal Api with a separate DbContext project throws error "Could not load information for ..."

Project Api

Project Data

Question

2 Answers2

Project `Api`

Project `Data`