AutoMapper

    public class Student
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
        public DateTime date { set; get; }
    }
    public class StudentDTO
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Age { get; set; }
        public string date { set; get; }
    }
    public class StudentActivityDTO
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Age { get; set; }
        public string datetime { set; get; }
    }

    public class StudentProfile : Profile
    {
        protected override void Configure()
        {
            //Student->StudentDTO
            //CreateMap<Student, StudentDTO>();
            //Student->StudentDTO
            CreateMap<Student, StudentDTO>()
                .ForMember(d => d.Id, opt => opt.MapFrom(s => s.Id))
                .ForMember(d => d.Name, opt => opt.MapFrom(s => s.Name))
                .ForMember(d => d.Age, opt => opt.MapFrom(s => s.Age.ToString() + " 岁"))
                .ForMember(d => d.date, opt => opt.MapFrom(s => string.Format("{0:yyyy-MM-dd}", s.date)));

            //Student->StudentActivityDTO
            CreateMap<Student, StudentActivityDTO>()
                .ForMember(d => d.Id, opt => opt.MapFrom(s => s.Id))
                .ForMember(d => d.Name, opt => opt.MapFrom(s => s.Name))
                .ForMember(d => d.Age, opt => opt.MapFrom(s => s.Age.ToString() + " 岁"))
                .ForMember(d => d.datetime, opt => opt.MapFrom(s => string.Format("{0:yyyy-MM-dd}", s.date)));
        }
    }

Mapper.CreateMap<Source, Destination>(); //直接依据字段名转换两个类

Student stu = new Student() { Id = 1, Name = "2", Age = 12, date = DateTime.Now };
StudentDTO stu_dto = Mapper.Map<StudentDTO>(stu);