public AdminDbContext()            : base("MemberDbContext")        {            //不使用代理创建导航属性，避免WCF序列化错误                Configuration.ProxyCreationEnabled = false;            //Configuration.LazyLoadingEnabled = false;        }        public DbSet<Employee> Employees { get; set; }        public DbSet<Role> Roles { get; set; }        protected override void OnModelCreating(DbModelBuilder modelBuilder)        {            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();            modelBuilder.Configurations.Add(new EmployeeMap());            modelBuilder.Configurations.Add(new RoleMap());            base.OnModelCreating(modelBuilder);        }        public int Commit()        {            return base.SaveChanges();        }

    public class EmployeeMap : EntityTypeConfiguration<Employee>    {        ......    }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)        {            var typesToRegister = Assembly.GetExecutingAssembly().GetTypes()            .Where(type => !String.IsNullOrEmpty(type.Namespace))            .Where(type => type.BaseType != null && type.BaseType.IsGenericType && type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>));            foreach (var type in typesToRegister)            {                dynamic configurationInstance = Activator.CreateInstance(type);                modelBuilder.Configurations.Add(configurationInstance);            }            //...or do it manually below. For example,            //modelBuilder.Configurations.Add(new LanguageMap());            base.OnModelCreating(modelBuilder);        }