Visual Studio, ASP .NET Core WebAPI, Add Controller Wizard (for EF) has stopped working

The scaffolding engine is failing to resolve the model type when running the “API Controller with actions, using Entity Framework” wizard. The key is to repair the scaffolding environment and EF tooling that the wizard depends on.

Use the following steps (in order) to restore the wizard:

1. Verify required scaffolding packages are present In the Web API project’s .csproj, ensure the following packages exist with compatible versions (for ASP.NET Core + EF Core):
   • Microsoft.VisualStudio.Web.CodeGeneration.Design
   • Microsoft.EntityFrameworkCore.Tools
   • Microsoft.EntityFrameworkCore.Design
   • The EF Core provider you use (for example Microsoft.EntityFrameworkCore.SqlServer)
   Visual Studio normally adds these automatically when scaffolding controllers or MVC pages, as shown in the MVC and Web API tutorials:
   • Microsoft.VisualStudio.Web.CodeGeneration.Design
   • Microsoft.EntityFrameworkCore.Tools
   • Microsoft.EntityFrameworkCore.SqlServer
   If any are missing, add them via NuGet and rebuild the solution.
2. Rebuild the solution before running the wizard The scaffolding engine uses reflection over the compiled assembly to find model and DbContext types. If the project is not building, or if the build is stale, the wizard may report messages like:
   • No properties found for --model 'CB'
   • --model 'CB' Invalid
   Build the solution (Build → Rebuild Solution) and confirm there are no compilation errors before opening the Add Controller wizard.
3. Confirm the model and context types are valid For the model type CB that the wizard is complaining about:
   • Ensure CB is a public class in the project (or referenced project) and compiles.
   • Ensure it has public properties (the scaffolder expects properties to generate CRUD code).
   • Ensure the DbContext used by the wizard exposes a DbSet<CB> property.
   The scaffolder for MVC and Web API controllers with EF requires a valid model class and a valid DbContext, similar to the examples where Student/SchoolContext, Movie/MvcMovieContext, or TodoItem/TodoContext are used.
4. Repair the scaffolding tool chain (CLI side) Even when using Visual Studio’s wizard, the underlying scaffolding engine is the same as the CLI dotnet-aspnet-codegenerator. If it is in a bad state, reinstalling it and its supporting packages can fix silent failures. In the project folder (where the .csproj lives), run:

      dotnet tool uninstall --global dotnet-aspnet-codegenerator
      dotnet tool install --global dotnet-aspnet-codegenerator
      dotnet tool update --global dotnet-aspnet-codegenerator
      
      dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design
      dotnet add package Microsoft.EntityFrameworkCore.Design
      dotnet add package Microsoft.EntityFrameworkCore.SqlServer
      dotnet add package Microsoft.EntityFrameworkCore.Tools
   

   Then rebuild the project.
5. Test scaffolding via CLI To verify that the scaffolding engine itself works for the CB model and its context (for example MyDbContext), run from the project folder:

      dotnet aspnet-codegenerator controller \
          -name CBController \
          -async -api \
          -m CB \
          -dc MyDbContext \
          -outDir Controllers
   

   If this succeeds, the underlying scaffolding engine is healthy; the Visual Studio wizard should also work again. If it fails with the same “No properties found” message, the issue is with the model or context definition (step 3).
6. Clear intermediate output and NuGet caches Since deleting bin/obj did not help, also clear NuGet caches and restore packages:
   • Close Visual Studio.
   • Delete bin and obj folders again.
   • Clear NuGet caches (for example via nuget locals all -clear or Visual Studio’s NuGet options).
   • Reopen the solution and let NuGet restore packages.
   • Rebuild and retry the wizard.
7. As a fallback, scaffold a similar controller and adjust If the wizard still fails specifically for CB but works for other models, scaffold a controller for a similar model that works, then copy/rename the generated controller and adjust the type names and DbSet usage manually. This avoids writing all methods from scratch while you continue to investigate why CB is being rejected.

These steps align with how ASP.NET Core scaffolding is expected to work in Visual Studio and via the CLI, and they address the typical causes of “No properties found for --model” and silent wizard failures.

References:

• Tutorial: Create a controller-based web API with ASP.NET Core
• Part 4, add a model to an ASP.NET Core MVC app
• Tutorial: Get started with EF Core in an ASP.NET MVC web app
• Add Models and Controllers