Entity Framework Core - Customise Scaffolding

Question

In Entity Framework 6 we can add the T4 templates the scaffolding uses by running

Install-Package EntityFramework.CodeTemplates.CSharp

But

Answer 1

In .Net Core 1.1, the way to override design-time services is to implement the IDesignTimeServices interface in the startup assembly. For example:

public class MyDesignTimeServices : IDesignTimeServices
{
    public void ConfigureDesignTimeServices(IServiceCollection serviceCollection)
    {
        serviceCollection.AddSingleton<EntityTypeWriter, MyEntityTypeWriter>();
        serviceCollection.AddSingleton<DbContextWriter, MybContextWriter>();

    }
}

See https://github.com/aspnet/EntityFramework/issues/5617

Answer 2

There is a special, yet-to-be-documented hook to override design-time services:

class Startup
{
    public static void ConfigureDesignTimeServices(IServiceCollection services)
        => services.AddSingleton<EntityTypeWriter, MyEntityTypeWriter>();
}

Then implement your custom generator.

class MyEntityTypeWriter : EntityTypeWriter
{
    public EntityTypeWriter(CSharpUtilities cSharpUtilities)
        : base(cSharpUtilities)
    {
    }

    // TODO: Override with custom implementation
}

Update: See Yehuda Goldenberg's answer for another way to do this in EF Core 1.0.2+.