Command "dotnet ef dbcontext scaffold Name=ConnectionString" with secrets.json fails with error "not found in the application's configuration" - dotnet-cli

Question

Running dotnet ef dbcontext scaffold name=con Microsoft.EntityFrameworkCore.SqlServer fails with ...the name 'con' was not found in the application's configuration. .... What is missing from the following sequence of steps?
Not a duplication!
.NET 6: how to get user-secrets working in a class library? is dealing with copying the <UserSecretsId> tag from one project to another, and moving from/to solution root dir. This question is much simpler:
Steps:
In an empty folder c:\my\temp\proj I ran the following commands:
dotnet new classlib -f net6.0
dotnet user-secrets init
dotnet user-secrets set con "my connection string"
Then examined proj.csproj and noticed that this entry was added:
<UserSecretsId>bce3b7d0-c6f7-4bd0-b808-841dbfd10bea</UserSecretsId>
And the new secrets.json which was created under:
%APPDATA%\Microsoft\UserSecrets\bce3b7d0-c6f7-4bd0-b808-841dbfd10bea\
Containing:
{
"con": "my connection string"
}
And then ran:
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet ef dbcontext scaffold name=con Microsoft.EntityFrameworkCore.SqlServer
Which eventually gave this error: A named connection string was used, but the name 'con' was not found in the application's configuration. Note that named connection strings are only supported when using 'IConfiguration' and a service provider, such as in a typical ASP.NET Core application. See https://go.microsoft.com/fwlink/?linkid=850912 for more information.
Even if I create an appsettings.json file containing e.g. { "con": "N/A" } I'm getting the same result.

Answer 1

I had the same issue, then I noticed the following message: Build failed. Use dotnet build to see the errors.
the result of this command was:
error MSB3021: Unable to copy file "obj\Debug\net6.0\Your_App_Name.dll" to "bin\Debug\net6.0\Your_App_Name.dll". The process cannot access the file 'C:\User
s\...\Your_App_Name.dll' because it is being used by another process.
I realize that I was running debug.. so I just stoped debug and ran command: dotnet ef dbcontext scaffold Name=ConnectionStrings:your_connection_name Microsoft.EntityFrameworkCore.SqlServer --output-dir Models -f
Maybe this could be the same issue you had 🤷‍♂️
reference: https://learn.microsoft.com/pt-br/ef/core/managing-schemas/scaffolding/?tabs=dotnet-core-cli