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  • 一句话的事儿：

一、最简单的用法

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. }
  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。

二、如果属性名称不同

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.  User user = new User()
  8.  {
  9.      Id = 1,
  10.      Name = "caoyc",
  11.      Age = 20
  12.  };
  13.  var dto = Mapper.Map<UserDto>(user);

C# AutoMapper 使用方式(03) - 图1

三、使用Profile配置

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>());
  3. User user = new User()
  4. {
  5.     Id = 1,
  6.     Name = "caoyc",
  7.     Age = 20
  8. };
  10. var dto = Mapper.Map<UserDto>(user);

四、空值替换NullSubstitute

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"));
  9.     }
  10. }
  1. Mapper.Initialize(x => x.AddProfile<UserProfile>());
  3. User user = new User()
  4. {
  5.     Id = 1,
  6.     Age = 20
  7. };
  9. var dto = Mapper.Map<UserDto>(user);

结果为：
C# AutoMapper 使用方式(03) - 图2

五、忽略属性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. }
  8. public class UserDto
  9. {
  10.     public string Name { get; set; }
  11.     public int Age { get; set; }
  13. }
  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>());
  3. User user = new User()
  4. {
  5.     Id = 1,
  6.     Name="caoyc",
  7.     Age = 20
  8. };
  10. var dto = Mapper.Map<UserDto>(user);

结果：
C# AutoMapper 使用方式(03) - 图3

六、预设值

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. }
  8. public class UserDto
  9. {
  10.     public string Name { get; set; }
  11.     public int Age { get; set; }
  12.     public string Gender { get; set; }
  14. }
  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>());
  3. User user = new User()
  4. {
  5.     Id = 1,
  6.     Name="caoyc",
  7.     Age = 20
  8. };
  10. UserDto dto = new UserDto() {Gender = "男"};
  11. Mapper.Map(user, dto);

C# AutoMapper 使用方式(03) - 图4

七、类型转换ITypeConverter

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. }
  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>();
  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. User user0 = new User() { Gender = 0 };
  3. User user1 = new User() { Gender = 1 };
  4. User user2 = new User() { Gender = 2 };
  5. var dto0= Mapper.Map<UserDto>(user0);
  6. var dto1 = Mapper.Map<UserDto>(user1);
  7. var dto2 = Mapper.Map<UserDto>(user2);
  8. Console.WriteLine("dto0:{0}", dto0.Gender);
  9. Console.WriteLine("dto1:{0}", dto1.Gender);
  10. Console.WriteLine("dto2:{0}", dto2.Gender);

结果
C# AutoMapper 使用方式(03) - 图5

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. }
  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. User user0 = new User() { Age = 1 };
  3. User user1 = new User() { Age = 150 };
  4. User user2 = new User() { Age = 201 };
  5. var dto0= Mapper.Map<UserDto>(user0);
  6. var dto1 = Mapper.Map<UserDto>(user1);
  7. var dto2 = Mapper.Map<UserDto>(user2);
  8. Console.WriteLine("dto0:{0}", dto0.Age);
  9. Console.WriteLine("dto1:{0}", dto1.Age);
  10. Console.WriteLine("dto2:{0}", dto2.Age);

输出结果
C# AutoMapper 使用方式(03) - 图6

  1. using System;  
  2. using System.Collections.Generic;  
  3. using System.Linq;  
  4. using System.Text;  
  5. using System.Threading.Tasks;  
  6. using AutoMapper;  
  7. using System.Data;  
  9. namespace ConsoleApplication2  
  10. {  
  11.     class Program  
  12.     {  
  14.         static void Main(string[] args)  
  15.         {  
  16.             //1.普通转换  
  17.             Name name1 = new Name() { FirstName = "L", LastName = "jz" };  
  18.             Mapper.CreateMap<Name, NameDto>()  
  19.             .BeforeMap((name, nameDto) => Console.WriteLine("hello world before"))  
  20.             .AfterMap((name, nameDto) => Console.WriteLine("hello world after"));  
  21.             NameDto nameDto1 = Mapper.Map<Name, NameDto>(name1);  
  22.             Console.WriteLine("1");  
  23.             Console.WriteLine(nameDto1.FirstName + nameDto1.LastName);  
  24.             Console.WriteLine();  
  25.             //Console.ReadKey();  
  27.             //整体设置  
  28.             //2.整体即时转换  
  29.             Mapper.Reset();  
  30.             Name name2 = new Name() { FirstName = "L", LastName = "jz" };  
  31.             Mapper.CreateMap<Name, NameDto>()  
  32.             .ConstructUsing(name => new NameDto() { AllName = name.FirstName + name.LastName });  
  33.             NameDto nameDto2 = Mapper.Map<Name, NameDto>(name2);  
  34.             Console.WriteLine("2");  
  35.             Console.WriteLine(nameDto2.AllName);  
  36.             Console.WriteLine();  
  37.             //Console.ReadKey();  
  39.             //3.整体通过TypeConverter类型转换  
  40.             Mapper.Reset();  
  41.             Name name3 = new Name() { FirstName = "L", LastName = "jz" };  
  42.             Mapper.CreateMap<Name, NameDto>()  
  43.             .ConvertUsing<NameConverter>();  
  44.             NameDto nameDto3 = Mapper.Map<Name, NameDto>(name3);  
  45.             Console.WriteLine("3");  
  46.             Console.WriteLine(nameDto3.AllName);  
  47.             Console.WriteLine();  
  48.             //Console.ReadKey();  
  50.             //单属性设置  
  51.             //4.属性条件转换  
  52.             Mapper.Reset();  
  53.             Name name4 = new Name() { FirstName = "L", LastName = "jz" };  
  54.             Mapper.CreateMap<Name, NameDto>()  
  55.             .ForMember(name => name.FirstName, opt => opt.Condition(name => !name.FirstName.Equals("l", StringComparison.OrdinalIgnoreCase)));  
  56.             NameDto nameDto4 = Mapper.Map<Name, NameDto>(name4);  
  57.             Console.WriteLine("4");  
  58.             Console.WriteLine(string.IsNullOrEmpty(nameDto4.FirstName));  
  59.             Console.WriteLine();  
  60.             //Console.ReadKey();  
  62.             //5.属性忽略  
  63.             Mapper.Reset();  
  64.             Name name5 = new Name() { FirstName = "L", LastName = "jz" };  
  65.             Mapper.CreateMap<Name, NameDto>()  
  66.             .ForMember(name => name.FirstName, opt => opt.Ignore());  
  67.             NameDto nameDto5 = Mapper.Map<Name, NameDto>(name5);  
  68.             Console.WriteLine("5");  
  69.             Console.WriteLine(string.IsNullOrEmpty(nameDto5.FirstName));  
  70.             Console.WriteLine();  
  71.             //Console.ReadKey();  
  73.             //6.属性转换  
  74.             Mapper.Reset();  
  75.             Name name6 = new Name() { FirstName = "L", LastName = "jz" };  
  76.             Mapper.CreateMap<Name, NameDto>()  
  77.             .ForMember(name => name.AllName, opt => opt.MapFrom(name => name.FirstName + name.LastName))  
  78.             .ForMember(name => name.FirstName, opt => opt.MapFrom(name=>name.FirstName));  
  79.             NameDto nameDto6 = Mapper.Map<Name, NameDto>(name6);  
  80.             Console.WriteLine("6");  
  81.             Console.WriteLine(nameDto6.AllName);  
  82.             Console.WriteLine();  
  83.             //Console.ReadKey();  
  85.             //7.属性通过ValueResolver转换  
  86.             Mapper.Reset();  
  87.             Name name7 = new Name() { FirstName = "L", LastName = "jz" };  
  88.             Mapper.CreateMap<Name, StoreDto>()  
  89.             .ForMember(storeDto => storeDto.Name, opt => opt.ResolveUsing<NameResolver>());  
  90.             StoreDto store1 = Mapper.Map<Name, StoreDto>(name7);  
  91.             Console.WriteLine("7");  
  92.             Console.WriteLine(store1.Name.FirstName + store1.Name.LastName);  
  93.             Console.WriteLine();  
  94.             //Console.ReadKey();  
  96.             //8.属性填充固定值  
  97.             Mapper.Reset();  
  98.             Name name8 = new Name() { FirstName = "L", LastName = "jz" };  
  99.             Mapper.CreateMap<Name, NameDto>()  
  100.             .ForMember(name => name.AllName, opt => opt.UseValue<string>("ljzforever"));  
  101.             NameDto nameDto8 = Mapper.Map<Name, NameDto>(name8);  
  102.             Console.WriteLine("8");  
  103.             Console.WriteLine(nameDto8.AllName);  
  104.             Console.WriteLine();  
  105.             //Console.ReadKey();  
  107.             //9.属性格式化  
  108.             Mapper.Reset();  
  109.             Name name9 = new Name() { FirstName = "L", LastName = "jz" };  
  110.             Mapper.CreateMap<Name, NameDto>()  
  111.             .ForMember(name => name.FirstName, opt => opt.AddFormatter<StringFormatter>());  
  112.             NameDto nameDto9 = Mapper.Map<Name, NameDto>(name9);  
  113.             Console.WriteLine("9");  
  114.             Console.WriteLine(nameDto9.FirstName);  
  115.             Console.WriteLine();  
  116.             //Console.ReadKey();  
  118.             //10.属性null时的默认值  
  119.             Mapper.Reset();  
  120.             Name name10 = new Name() { FirstName = "L" };  
  121.             Mapper.CreateMap<Name, NameDto>()  
  122.             .ForMember(name => name.LastName, opt => opt.NullSubstitute("jz"));  
  123.             NameDto nameDto10 = Mapper.Map<Name, NameDto>(name10);  
  124.             Console.WriteLine("10");  
  125.             Console.WriteLine(nameDto10.LastName);  
  126.             Console.WriteLine();  
  127.             //Console.ReadKey();  
  129.             //其它设置与特性  
  130.             //11.转换匿名对象  
  131.             Mapper.Reset();  
  132.             object name11 = new { FirstName = "L", LastName = "jz" };  
  133.             NameDto nameDto11 = Mapper.DynamicMap<NameDto>(name11);  
  134.             Console.WriteLine("11");  
  135.             Console.WriteLine(nameDto11.FirstName + nameDto11.LastName);  
  136.             Console.WriteLine();  
  137.             //Console.ReadKey();  
  139.             //12.转换DataTable  
  140.             Mapper.Reset();  
  141.             DataTable dt = new DataTable();  
  142.             dt.Columns.Add("FirstName", typeof(string));  
  143.             dt.Columns.Add("LastName", typeof(string));  
  144.             dt.Rows.Add("L", "jz");  
  145.             List<NameDto> nameDto12 = Mapper.DynamicMap<IDataReader, List<NameDto>>(dt.CreateDataReader());  
  146.             Console.WriteLine("12");  
  147.             Console.WriteLine(nameDto12[0].FirstName + nameDto12[0].LastName);  
  148.             Console.WriteLine();  
  149.             //Console.ReadKey();  
  150.             //emitMapper error  
  151.             //List<NameDto> nameDto20 = EmitMapper.ObjectMapperManager.DefaultInstance.GetMapper<IDataReader, List<NameDto>>().Map(dt.CreateDataReader());  
  154.             //13.转化存在的对象  
  155.             Mapper.Reset();  
  156.             Mapper.CreateMap<Name, NameDto>()  
  157.             .ForMember(name => name.LastName, opt => opt.Ignore());  
  158.             Name name13 = new Name() { FirstName = "L" };  
  159.             NameDto nameDto13 = new NameDto() { LastName = "jz" };  
  160.             Mapper.Map<Name, NameDto>(name13, nameDto13);  
  161.             //nameDto13 = Mapper.Map<Name, NameDto>(name13);//注意,必需使用上面的写法,不然nameDto13对象的LastName属性会被覆盖  
  162.             Console.WriteLine("13");  
  163.             Console.WriteLine(nameDto13.FirstName + nameDto13.LastName);  
  164.             Console.WriteLine();  
  165.             //Console.ReadKey();  
  167.             //14.Flatten特性 Store.Name.FirtName=FlattenName.NameFirstname  
  168.             Mapper.Reset();  
  169.             Mapper.CreateMap<Store, FlattenName>();  
  170.             Store store2 = new Store() { Name = new Name() { FirstName = "L", LastName = "jz" } };  
  171.             FlattenName nameDto14 = Mapper.Map<Store, FlattenName>(store2);  
  172.             Console.WriteLine("14");  
  173.             Console.WriteLine(nameDto14.NameFirstname + nameDto14.NameLastName);  
  174.             Console.WriteLine();  
  175.             //Console.ReadKey();  
  177.             //15.将Dictionary转化为对象,现在还不支持  
  178.             Mapper.Reset();  
  179.             Mapper.CreateMap<Dictionary<string, object>, Name>();  
  180.             Dictionary<string, object> dict = new Dictionary<string, object>();  
  181.             dict.Add("FirstName", "L");  
  182.             //Name name15 = Mapper.DynamicMap<Dictionary<string, object>, Name>(dict);  
  183.             Name name15 = Mapper.Map<Dictionary<string, object>, Name>(dict);  
  184.             Console.WriteLine("15");  
  185.             Console.WriteLine(name15.FirstName);  
  186.             Console.WriteLine();  
  187.             Console.ReadKey();  
  188.         }  
  189.     }  
  192.     public class Store  
  193.     {  
  194.         public Name Name { get; set; }  
  195.         public int Age { get; set; }  
  196.     }  
  198.     public class Name  
  199.     {  
  200.         public string FirstName { get; set; }  
  201.         public string LastName { get; set; }  
  202.     }  
  204.     public class StoreDto  
  205.     {  
  206.         public NameDto Name { get; set; }  
  207.         public int Age { get; set; }  
  208.     }  
  210.     public class NameDto  
  211.     {  
  212.         public string FirstName { get; set; }  
  213.         public string LastName { get; set; }  
  214.         public string AllName { get; set; }  
  215.     }  
  217.     public class FlattenName  
  218.     {  
  219.         public string NameFirstname { get; set; }  
  220.         public string NameLastName { get; set; }  
  221.     }  
  223.     public class NameConverter : TypeConverter<Name, NameDto>  
  224.     {  
  225.         protected override NameDto ConvertCore(Name source)  
  226.         {  
  227.             return new NameDto() { AllName = source.FirstName + source.LastName };  
  228.         }  
  229.     }  
  231.     public class NameResolver : ValueResolver<Name, NameDto>  
  232.     {  
  233.         protected override NameDto ResolveCore(Name source)  
  234.         {  
  235.             return new NameDto() { FirstName = source.FirstName, LastName = source.LastName,AllName=source.FirstName+source.LastName };  
  236.         }  
  237.     }  
  239.     public class NameFormatter : ValueFormatter<NameDto>  
  240.     {  
  241.         protected override string FormatValueCore(NameDto name)  
  242.         {  
  243.             return name.FirstName + name.LastName;  
  244.         }  
  245.     }  
  247.     public class StringFormatter : ValueFormatter<string>  
  248.     {  
  249.         protected override string FormatValueCore(string name)  
  250.         {  
  251.             return name + "-";  
  252.         }  
  253.     }  
  254. }
  • 本文作者：GeekPower - Felix Sun
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