在添加迁移期间忽略引用程序集中的实体

我有一个项目，我的域在一堆单独的程序集和DbContexts之间分裂，所有使用相同的底层Sql Server数据库。除了一个例外，这些程序集不能相互引用——有一个程序集包含可以称为共享实体的内容，这些内容对所有其他域都是通用的，有时作为导航属性引用。简化的例子:

// Shared.dll
namespace Shared
{
   // Shared POCO
   class Hero
   {
       public string Name { get; set; }
       public string Description { get; set; }
   }
   class MyDbContext : DbContext
   {
       public virtual DbSet<Hero> Heroes { get; set; }
   } 
   internal sealed class MyDbContextConfiguration : DbMigrationsConfiguration<MyDbContext>
   {
       public MyDbContextConfiguration ()
       {
           AutomaticMigrationsEnabled = false;
           MigrationsDirectory = @"Migrations'MyDbContext";
           ContextKey = "Shared";
       }
   }
}
// Game.dll <- references Shared.dll
namespace Game
{
   // Individual POCO
   class Mission
   {
       public string Name { get; set; }
       public virtual ICollection<Hero> Protagonists { get; set; }
   }
   class MyDbContext : DbContext
   {
       public virtual DbSet<Mission> Missions { get; set; }
   } 
   internal sealed class MyDbContextConfiguration : DbMigrationsConfiguration<MyDbContext>
   {
       public MyDbContextConfiguration ()
       {
           AutomaticMigrationsEnabled = false;
           MigrationsDirectory = @"Migrations'MyDbContext";
           ContextKey = "Game";
       }
   }
}

问题是，当我通过ICollection<Hero> Protagonists导航属性在Game.dll组装模型中引用Hero POCO时，调用:

add-migration Test -ProjectName:Game -ConfigurationTypeName MyDbContextConfiguration -StartUpProjectName Main

最终创建DbMigration，其中包括从引用的Shared.dll程序集对Hero实体的更改。

    public partial class Test : DbMigration
    {
        public override void Up()
        {
            AddColumn("shared.Heroes", "Name", c => c.String());
            AddColumn("shared.Heroes", "Description", c => c.String());
            ...

我如何将add-migration限制为仅监视位于定义DbContext的程序集中的实体的更改?换句话说，当对Games.dll运行add-migration时，我想忽略对Shared.dll中的实体所做的任何更改。

还可以通过名称空间或数据库对象来限制模式。我只是不希望对位于引用程序集中的实体的任何更改包含在我的迁移中，因为所有的迁移都是按程序集维护的。

 public class MyDbContext : DbContext
 {
   private readonly bool _isMigrationMode;
   public MyDbContext()
   {
     // This used by migration default and you can give the connection string in the command line.
     _isMigrationMode = true;
   }
   // isMigrationMode: I have give it here as an optional parameter, in case, if you want to create the migration from the code.
   public MyDbContext(string connectionString, bool isMigrationMode = false)
         : base("name=" + connectionString)
   {
     _isMigrationMode = isMigrationMode;
   }
   protected override void OnModelCreating(DbModelBuilder modelBuilder)
   {
     if (_isMigrationMode)
     {
       modelBuilder.Ignore<Hero>();
     }
     base.OnModelCreating(modelBuilder);
   }
   public DbSet<Mission> Missions { get; set; }
 }

 public partial class FirstDb : DbMigration
 {
     public override void Up()
     {
         CreateTable(
             "dbo.Missions",
             c => new
                 {
                     MissionId = c.Long(nullable: false, identity: true),
                     Amount = c.Int(nullable: false),
                     Amount2 = c.Int(nullable: false),
                     HeroId = c.Long(nullable: false),
                 })
             .PrimaryKey(t => t.MissionId);
     }
     public override void Down()
     {
         DropTable("dbo.Missions");
     }
 }