EF Core update-database Build Failed-CodePudding

I created a very simple app, and thought I configured everything as it should.

I installed Entity Framework Core for SQL Server and Tools nuget packages.

I created 2 model classes:

public class Make
{
    public int Id { get; set; }
    public string Name { get; set; }    
}

public class Model
{
    public int Id { get; set; }
    public string Name { get; set; }

    public Make Make { get; set; }

    [ForeignKey("Make")]
    public int MakeFK { get; set; }
}

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
    {
    }

    public DbSet<Make> Makes { get; set; }
    public DbSet<Model> Models { get; set; }
}

In Program.cs I added these lines of code:

builder.Services.AddDbContext<AppDbContext>(options =>
{
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});

And in appsettings.json, I added the connection string:

"ConnectionStrings": {
    "DefaultConnection": "Data Source =localhost; Database=vRoom; Integrated Security=True; Pooling=False"
},

Now I did all this multiple times in the past and have had no issues. When I build I get no errors.

In the console I run:

 add-migration "initial"

Folder Migrations is created, with _initial, and also Snapshot.cs file.

After the first command I run:

 update-database

But I get a BuildStart.... then BuildFailed error (nothing else)

I try to build the solution again and now I get an error. In the Migrations Snapshot.cs file there is something that was created and it gives me an error:

[DbContext(typeof(AppDbContext))]

Error says

AppDbContext is a namespace but is used as a type

I have not seen this before even though I've ran probably a dozen migrations in my other app.

Any pointers?

EDIT: I noticed in my older project that I had EF 6.0.8, the version I'm using today is 6.0.9

CodePudding user response：

The reason why you got this error is class and namespace have the same name.

Your project structure may be：

namespace xxx.AppDbContext 
{
    public class AppDbContext 
    {
    }
}

The solution to this issue is make class and namespace have different name:

namespace xxx.MyDbContext 
    {
        public class AppDbContext 
        {
        }
    }

You can read Do not name a class the same as its namespace to Learn More details

CodePudding user response：

I assume that you have folder structure like below:

Project > Model > AppDbContext

as per above folder structure you class was generated like below:

namespace Project.Model.AppDbContext // this name space cause your migration as per error message
{
   public class AppDbContext : DbContext
   {
       public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
       {
       }

       public DbSet<Make> Makes { get; set; }
       public DbSet<Model> Models { get; set; }
   }
}

Change your namespace Project.Model.AppDbContext with namespace Project.Model.AppDbContextABC then it will work fine.