Consider using IDbContextFactory to override the initialization of the DbContext at design-time

Question

On an ASP.NET Core 1.0.1 project, using Entity Framework Core and ASP.NET Identity, I have the following context:

public class Context : IdentityDbContext<User, Role, Int32, UserClaim, UserRole, UserLogin, RoleClaim, UserToken> { 
  public Context(DbContextOptions options) : base(options) { }
  protected override void OnModelCreating(ModelBuilder builder) {
   base.OnModelCreating(builder);
  }
}

And the following entities:

public class User : IdentityUser<Int32, UserClaim, UserRole, UserLogin> { }
public class Role : IdentityRole<Int32, UserRole, RoleClaim> { }
public class RoleClaim : IdentityRoleClaim<Int32> { }
public class UserClaim : IdentityUserClaim<Int32> { }
public class UserLogin : IdentityUserLogin<Int32> { }
public class UserRole : IdentityUserRole<Int32> { }
public class UserToken : IdentityUserToken<Int32> { }

On Startup I have the following:

services.AddDbContext<Context>(x => x.UseSqlServer(connectionString, y => y.MigrationsHistoryTable("__Migrations")));

services
  .AddIdentity<User, Role>()
  .AddEntityFrameworkStores<Context, Int32>()
  .AddDefaultTokenProviders();

When I run dotnet ef migrations add "FirstMigration" I get the following error:

An error occurred while calling method 'ConfigureServices' on startup class 'WebProject.Startup'. Consider using IDbContextFactory to override the initialization of the DbContext at design-time. Error: GenericArguments[0], 'WebProject.User', on 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore`4[TUser,TRole,TContext,TKey]' violates the constraint of type 'TUser'.

How to solve this problem?

Are you going to write any custom code inside RoleClaim, UserClaim, UserLogin, UserRole, UserToken? If not you can simply inherit from `Context : IdentityDbContext`, `User : IdentityUser` and `Role : IdentityRole` — tmg, Sep 19 '16 at 18:28
@tmg I might need to write some custom code in those ... That is why I am using it this way. And MSFT added that option in https://github.com/aspnet/Identity/blob/dev/src/Microsoft.AspNetCore.Identity.EntityFrameworkCore/IdentityDbContext.cs#L84 I am just now sure why I am having this problem as it seems everything is fine — Miguel Moura, Sep 19 '16 at 21:50
I am not sure where the error comes from and why I get the suggestion 'Consider using IDbContextFactory' — Miguel Moura, Sep 19 '16 at 22:09
Facing the same problem, just share my thoughts and still investigating... sounds like DI/Generics issue. perhaps what we need is a custom UserStore! — Hossam, Sep 20 '16 at 19:17
try dotnet ef migrations add "FirstMigration" --verbose It will give you the full stacktrace, potentially identifying the source of the error — Segmentation Fault, Nov 03 '16 at 04:38

Gerardo Grignoli · Answer 1 · 2017-09-15T18:24:37.840

5

I apologise for posting a partial answer but it will be usefull for many...

An error occurred while calling method 'ConfigureServices' on startup class

Your method Startup.ConfigureServices(...) is being called and it is throwing an exception. The exception probably happens because when running dotnet ef the application entry point is not Program.Main() as usual.

Try

    dotnet ef migrations add "FirstMigration" --verbose

That will print the error message and you will be able to better understand the issue.

edited Sep 15 '17 at 18:24

answered Oct 19 '16 at 03:14

Gerardo Grignoli

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Learning Program.Main() was not entry point along with dotnet ef migrations add "FirstMigration" --verbose helped me solve this. – ttugates Mar 27 '17 at 21:16

Consider using IDbContextFactory to override the initialization of the DbContext at design-time

1 Answers1