有两个类User和UserDto
1 public class User
2 {
3 public int Id { get; set; }
4 public string Name { get; set; }
5 public int Age { get; set; }
6 }
7
8 public class UserDto
9 {
10 public string Name { get; set; }
11 public int Age { get; set; }
12 }
将User转换成UserDto也和简单
1 Mapper.Initialize(x => x.CreateMap<User, UserDto>());
2 User user = new User()
3 {
4 Id = 1,
5 Name = "caoyc",
6 Age = 20
7 };
8 var dto = Mapper.Map<UserDto>(user);
这是一种最简单的使用，AutoMapper会更加字段名称去自动对于，忽略大小写。
将UserDto的Name属性改成Name2
1 Mapper.Initialize(x =>
2 x.CreateMap<User, UserDto>()
3 .ForMember(d =>d.Name2, opt => {
4 opt.MapFrom(s => s.Name);
5 })
6 );
7
8 User user = new User()
9 {
10 Id = 1,
11 Name = "caoyc",
12 Age = 20
13 };
14
15 var dto = Mapper.Map<UserDto>(user);
自定义一个UserProfile类继承Profile，并重写Configure方法
1 public class UserProfile : Profile
2 {
3 protected override void Configure()
4 {
5 CreateMap<User, UserDto>()
6 .ForMember(d => d.Name2, opt =>
7 {
8 opt.MapFrom(s => s.Name);
9 });
10 }
11 }
使用时就这样
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user = new User()
4 {
5 Id = 1,
6 Name = "caoyc",
7 Age = 20
8 };
9
10 var dto = Mapper.Map<UserDto>(user);
空值替换允许我们将Source对象中的空值在转换为Destination的值的时候，使用指定的值来替换空值。
1 public class UserProfile : Profile
2 {
3 protected override void Configure()
4 {
5 CreateMap<User, UserDto>()
6 .ForMember(d => d.Name2, opt => opt.MapFrom(s => s.Name))
7 .ForMember(d => d.Name2, opt => opt.NullSubstitute("值为空"));
8
9 }
10 }
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user = new User()
4 {
5 Id = 1,
6 Age = 20
7 };
8
9 var dto = Mapper.Map<UserDto>(user);
结果为：
1 public class User
2 {
3 public int Id { get; set; }
4 public string Name { get; set; }
5 public int Age { get; set; }
6 }
7
8 public class UserDto
9 {
10 public string Name { get; set; }
11 public int Age { get; set; }
12
13 }
14
15 public class UserProfile : Profile
16 {
17 protected override void Configure()
18 {
19 CreateMap<User, UserDto>().ForMember("Name", opt => opt.Ignore());
20 }
21 }
使用
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user = new User()
4 {
5 Id = 1,
6 Name="caoyc",
7 Age = 20
8 };
9
10 var dto = Mapper.Map<UserDto>(user);
结果：
如果目标属性多于源属性，可以进行预设值
1 public class User
2 {
3 public int Id { get; set; }
4 public string Name { get; set; }
5 public int Age { get; set; }
6 }
7
8 public class UserDto
9 {
10 public string Name { get; set; }
11 public int Age { get; set; }
12 public string Gender { get; set; }
13
14 }
15
16 public class UserProfile : Profile
17 {
18 protected override void Configure()
19 {
20 CreateMap<User, UserDto>();
21 }
22 }
使用
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user = new User()
4 {
5 Id = 1,
6 Name="caoyc",
7 Age = 20
8 };
9
10 UserDto dto = new UserDto() {Gender = "男"};
11 Mapper.Map(user, dto);
如果数据中Gender存储的int类型，而DTO中Gender是String类型
1 public class User
2 {
3 public int Gender { get; set; }
4 }
5
6 public class UserDto
7 {
8 public string Gender { get; set; }
9 }
类型转换类，需要实现接口ITypeConverter
1 public class GenderTypeConvertert : ITypeConverter<int, string>
2 {
3 public string Convert(int source, string destination, ResolutionContext context)
4 {
5 switch (source)
6 {
7 case 0:
8 destination = "男";
9 break;
10 case 1:
11 destination = "女";
12 break;
13 default:
14 destination = "未知";
15 break;
16 }
17 return destination;
18 }
19 }
配置规则
1 public class UserProfile : Profile
2 {
3 protected override void Configure()
4 {
5 CreateMap<User, UserDto>();
6
7 CreateMap<int, string>().ConvertUsing<GenderTypeConvertert>();
8 //也可以写这样
9 //CreateMap<int, string>().ConvertUsing(new GenderTypeConvertert());
10 }
11 }
使用
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user0 = new User() { Gender = 0 };
4 User user1 = new User() { Gender = 1 };
5 User user2 = new User() { Gender = 2 };
6 var dto0= Mapper.Map<UserDto>(user0);
7 var dto1 = Mapper.Map<UserDto>(user1);
8 var dto2 = Mapper.Map<UserDto>(user2);
9
10 Console.WriteLine("dto0:{0}", dto0.Gender);
11 Console.WriteLine("dto1:{0}", dto1.Gender);
12 Console.WriteLine("dto2:{0}", dto2.Gender);
结果
八、条件约束Condition
当满足条件时才进行映射字段，例如人类年龄，假设我们现在人类年龄范围为0-200岁（这只是假设），只有满足在这个条件才进行映射
DTO和Entity
1 public class User
2 {
3 public int Age { get; set; }
4 }
5
6 public class UserDto
7 {
8 public int Age { get; set; }
9 }
Profile
1 public class UserProfile : Profile
2 {
3 protected override void Configure()
4 {
5 CreateMap<User, UserDto>().ForMember(dest=>dest.Age,opt=>opt.Condition(src=>src.Age>=0 && src.Age<=200));
6 }
7 }
使用代码
1 Mapper.Initialize(x => x.AddProfile<UserProfile>());
2
3 User user0 = new User() { Age = 1 };
4 User user1 = new User() { Age = 150 };
5 User user2 = new User() { Age = 201 };
6 var dto0= Mapper.Map<UserDto>(user0);
7 var dto1 = Mapper.Map<UserDto>(user1);
8 var dto2 = Mapper.Map<UserDto>(user2);
9
10 Console.WriteLine("dto0:{0}", dto0.Age);
11 Console.WriteLine("dto1:{0}", dto1.Age);
12 Console.WriteLine("dto2:{0}", dto2.Age);
输出结果
转载 c# automapper 使用(一) https://www.cnblogs.com/caoyc/p/6367828.html
原文：https://www.cnblogs.com/Jeely/p/10716067.html