Add migration with different assembly

Question

I am working on a project with ASP.NET CORE 1.0.0 and I am using EntityFrameworkCore. I have separate assemblies and my project structure looks like this:

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Answer 1

Using EF Core 2, you can easily separate your Web project from your Data (DbContext) project. In fact, you just need to implement the IDesignTimeDbContextFactory interface. According to Microsoft docs, IDesignTimeDbContextFactory is:

A factory for creating derived DbContext instances. Implement this interface to enable design-time services for context types that do not have a public default constructor. At design-time, derived DbContext instances can be created in order to enable specific design-time experiences such as Migrations. Design-time services will automatically discover implementations of this interface that are in the startup assembly or the same assembly as the derived context.

In the bottom code snippet you can see my implementation of DbContextFactory which is defined inside my Data project:

public class DbContextFactory : IDesignTimeDbContextFactory
{
    public KuchidDbContext CreateDbContext(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();

        var dbContextBuilder = new DbContextOptionsBuilder();

        var connectionString = configuration.GetConnectionString("Kuchid");

        dbContextBuilder.UseSqlServer(connectionString);

        return new KuchidDbContext(dbContextBuilder.Options);
    }
}

Now, I can initialize EF migration by setting my Web project as the StartUp project and selecting my Data project inside the Package Manager Console.

Add-Migration initial

You can find more details here. However, this blog post uses an obsoleted class instead of IDesignTimeDbContextFactory.