Specify which project file to use because this [directory] contains more than one project file.

[piotrek-k]

I've encountered a problem while trying to execute dotnet ef migrations add [migration_name] command.
While creating new project in Visual Studio 2019, I've marked an option "Place solution and project in the same directory". Here is how my project structure looks like:

λ ls
App.razor               Data/                Pages/       Shared/                       appsettings.json       docker-compose.override.yml
Areas/                  Dockerfile           Program.cs   Startup.cs                    bin/                   docker-compose.yml
BlazorApp1.csproj       Dockerfile.original  Properties/  _Imports.razor                blazor_app.sln         obj/
BlazorApp1.csproj.user  Models/              Services/    appsettings.Development.json  docker-compose.dcproj  wwwroot/

When I try to execute above mentioned command, I receive this message:

λ dotnet ef migrations add migrationname
Specify which project file to use because this 'C:\Users\piotr\Desktop\webserver\blazor_app' contains more than one project file.

It makes sense, since I've got BlazorApp1.csproj and docker-compose.dcproj which are project files in the same folder. But at the same time there is no way to specify which project I want to use.
People on the internet recommend to use -p and -s arguments, but documentation says that those arguments can specify path to the project folder not project file.
Nonetheless I tried to use them in such way, but with no luck.

C:\Users\piotr\Desktop\webserver\blazor -> origin_app (blazor -> origin)
λ dotnet ef -p BlazorApp1.csproj
Specify which project file to use because this 'C:\Users\piotr\Desktop\webserver\blazor_app' contains more than one project file.

C:\Users\piotr\Desktop\webserver\blazor -> origin_app (blazor -> origin)
λ dotnet ef -p BlazorApp1.csproj -s BlazorApp1.csproj
Specify which project file to use because this 'C:\Users\piotr\Desktop\webserver\blazor_app' contains more than one project file.

It's also worth noting I couldn't even view help to see possible parameters I could use because of this error:

λ dotnet ef --help
Specify which project file to use because this 'C:\Users\piotr\Desktop\webserver\blazor_app' contains more than one project file.

Summing up, a few things, in my opinion, should be fixed:

• add parameter to specify which project I want to use for migration
• OR remove "Place solution and project in the same directory" option from Visual Studio if it creates illegal project structure
• allow to view CLI help regardless of error

[urumo]

For the devs, this is still a thing

[marcpopMSFT]

Old issue triage: @ajcvickers for ef. Not sure if this is still an issue.