轉載 c# automapper 使用(一) https://www.cnblogs.com/caoyc/p/6367828.html
阿新 • • 發佈：2019-04-16
type 代碼 clas 約束 orm html efault () com 
一、最簡單的用法
有兩個類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 }
將User轉換成UserDto也和簡單
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);
這是一種最簡單的使用，AutoMapper會更加字段名稱去自動對於，忽略大小寫。
二、如果屬性名稱不同
將UserDto的Name屬性改成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);
三、使用Profile配置
自定義一個UserProfile類繼承Profile，並重寫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 }
使用時就這樣
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);
四、空值替換NullSubstitute
空值替換允許我們將Source對象中的空值在轉換為Destination的值的時候，使用指定的值來替換空值。
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("值為空"));
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);
結果為：
五、忽略屬性Ignore
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);
結果：
六、預設值
如果目標屬性多於源屬性，可以進行預設值
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);
七、類型轉換ITypeConverter
如果數據中Gender存儲的int類型，而DTO中Gender是String類型
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 }
類型轉換類，需要實現接口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 }
配置規則
1 public class UserProfile : Profile
2 {
3 protected override void Configure()
4 {
5 CreateMap<User, UserDto>();
6
7 CreateMap<int, string>().ConvertUsing<GenderTypeConvertert>();
8 //也可以寫這樣
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);
結果
八、條件約束Condition
當滿足條件時才進行映射字段，例如人類年齡，假設我們現在人類年齡範圍為0-200歲（這只是假設），只有滿足在這個條件才進行映射
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 }
使用代碼
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);
輸出結果
轉載 c# automapper 使用(一) https://www.cnblogs.com/caoyc/p/6367828.html