Area类

       public virtual User User { get; set; }

User类

        public virtual Area Area { get; set; }

Context类

            modelBuilder.Entity<Area>()                        //巡检区域-区域负责人    

           .HasOptional(a => a.User)            

          .WithOptionalDependent()            

          .Map(x => x.MapKey("UserID"));

            modelBuilder.Entity<User>()                        //巡检区域-区域负责人            

           .HasOptional(u => u.Area)            

           .WithOptionalDependent()            

          .Map(x => x.MapKey("AreaID"));

Entity创建一对一关系