问题
I have a brand-new ASP.NET MVC 5 project with one DbContext using Entity Framework 6.1 and Identity 2.2.1. Trying go use IoC, I created a 2nd DbContext and some classes belonging to that 2nd context.
Most of these classes have a foreign key to the IdentityUser class within Identity 2.2.1. The problem I'm having is that when I try to use Add-Migrations I get the following error:
One or more validation errors were detected during model generation:
{MyProjectName}.DataContexts.IdentityUserLogin: : EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType.
{MyProjectName}.DataContexts.IdentityUserRole: : EntityType 'IdentityUserRole' has no key defined. Define the key for this EntityType.
IdentityUserLogins: EntityType: EntitySet 'IdentityUserLogins' is based on type 'IdentityUserLogin' that has no keys defined.
IdentityUserRoles: EntityType: EntitySet 'IdentityUserRoles' is based on type 'IdentityUserRole' that has no keys defined.
When I move the classes I created from my 2nd context into the initial context, I don't get any error and the database table build as expected.
How can I keep IoC AND have foreign key restrictions work properly with EF and CodeFirst?
Sample
You can find a sample project at https://github.com/RoLYroLLs/MultiDbContextForeignKeySample. To recreate the error run this on the Package Manager Console:
Enable-Migrations -MigrationsDirectory "DataContexts\ClientMigrations" -ContextTypeName MultiDbContextForeignKeySample.DataContexts.ClientDbContext
来源：https://stackoverflow.com/questions/34255335/using-foreign-keys-with-different-contexts-using-entity-framework-code-first