c# automapper 使用

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     }

 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。

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

 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);

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"));

 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：

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     }

 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：

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     }

 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、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     }

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

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using AutoMapper;

using System.Data;  

namespace ConsoleApplication2

{

    class Program

    {  

        static void Main(string[] args)

        {

            //1.普通转换

            Name name1 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .BeforeMap((name, nameDto) => Console.WriteLine("hello world before"))

            .AfterMap((name, nameDto) => Console.WriteLine("hello world after"));

            NameDto nameDto1 = Mapper.Map<Name, NameDto>(name1);

            Console.WriteLine("");

            Console.WriteLine(nameDto1.FirstName + nameDto1.LastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //整体设置

            //2.整体即时转换

            Mapper.Reset();

            Name name2 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ConstructUsing(name => new NameDto() { AllName = name.FirstName + name.LastName });

            NameDto nameDto2 = Mapper.Map<Name, NameDto>(name2);

            Console.WriteLine("");

            Console.WriteLine(nameDto2.AllName);

            Console.WriteLine();

            //Console.ReadKey();  

            //3.整体通过TypeConverter类型转换

            Mapper.Reset();

            Name name3 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ConvertUsing<NameConverter>();

            NameDto nameDto3 = Mapper.Map<Name, NameDto>(name3);

            Console.WriteLine("");

            Console.WriteLine(nameDto3.AllName);

            Console.WriteLine();

            //Console.ReadKey();  

            //单属性设置

            //4.属性条件转换

            Mapper.Reset();

            Name name4 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.FirstName, opt => opt.Condition(name => !name.FirstName.Equals("l", StringComparison.OrdinalIgnoreCase)));

            NameDto nameDto4 = Mapper.Map<Name, NameDto>(name4);

            Console.WriteLine("");

            Console.WriteLine(string.IsNullOrEmpty(nameDto4.FirstName));

            Console.WriteLine();

            //Console.ReadKey();  

            //5.属性忽略

            Mapper.Reset();

            Name name5 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.FirstName, opt => opt.Ignore());

            NameDto nameDto5 = Mapper.Map<Name, NameDto>(name5);

            Console.WriteLine("");

            Console.WriteLine(string.IsNullOrEmpty(nameDto5.FirstName));

            Console.WriteLine();

            //Console.ReadKey();  

            //6.属性转换

            Mapper.Reset();

            Name name6 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.AllName, opt => opt.MapFrom(name => name.FirstName + name.LastName))

            .ForMember(name => name.FirstName, opt => opt.MapFrom(name=>name.FirstName));

            NameDto nameDto6 = Mapper.Map<Name, NameDto>(name6);

            Console.WriteLine("");

            Console.WriteLine(nameDto6.AllName);

            Console.WriteLine();

            //Console.ReadKey();  

            //7.属性通过ValueResolver转换

            Mapper.Reset();

            Name name7 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, StoreDto>()

            .ForMember(storeDto => storeDto.Name, opt => opt.ResolveUsing<NameResolver>());

            StoreDto store1 = Mapper.Map<Name, StoreDto>(name7);

            Console.WriteLine("");

            Console.WriteLine(store1.Name.FirstName + store1.Name.LastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //8.属性填充固定值

            Mapper.Reset();

            Name name8 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.AllName, opt => opt.UseValue<string>("ljzforever"));

            NameDto nameDto8 = Mapper.Map<Name, NameDto>(name8);

            Console.WriteLine("");

            Console.WriteLine(nameDto8.AllName);

            Console.WriteLine();

            //Console.ReadKey();  

            //9.属性格式化

            Mapper.Reset();

            Name name9 = new Name() { FirstName = "L", LastName = "jz" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.FirstName, opt => opt.AddFormatter<StringFormatter>());

            NameDto nameDto9 = Mapper.Map<Name, NameDto>(name9);

            Console.WriteLine("");

            Console.WriteLine(nameDto9.FirstName);

            Console.WriteLine();

            //Console.ReadKey();  

            //10.属性null时的默认值

            Mapper.Reset();

            Name name10 = new Name() { FirstName = "L" };

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.LastName, opt => opt.NullSubstitute("jz"));

            NameDto nameDto10 = Mapper.Map<Name, NameDto>(name10);

            Console.WriteLine("");

            Console.WriteLine(nameDto10.LastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //其它设置与特性

            //11.转换匿名对象

            Mapper.Reset();

            object name11 = new { FirstName = "L", LastName = "jz" };

            NameDto nameDto11 = Mapper.DynamicMap<NameDto>(name11);

            Console.WriteLine("");

            Console.WriteLine(nameDto11.FirstName + nameDto11.LastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //12.转换DataTable

            Mapper.Reset();

            DataTable dt = new DataTable();

            dt.Columns.Add("FirstName", typeof(string));

            dt.Columns.Add("LastName", typeof(string));

            dt.Rows.Add("L", "jz");

            List<NameDto> nameDto12 = Mapper.DynamicMap<IDataReader, List<NameDto>>(dt.CreateDataReader());

            Console.WriteLine("");

            Console.WriteLine(nameDto12[].FirstName + nameDto12[].LastName);

            Console.WriteLine();

            //Console.ReadKey();

            //emitMapper error

            //List<NameDto> nameDto20 = EmitMapper.ObjectMapperManager.DefaultInstance.GetMapper<IDataReader, List<NameDto>>().Map(dt.CreateDataReader());  

            //13.转化存在的对象

            Mapper.Reset();

            Mapper.CreateMap<Name, NameDto>()

            .ForMember(name => name.LastName, opt => opt.Ignore());

            Name name13 = new Name() { FirstName = "L" };

            NameDto nameDto13 = new NameDto() { LastName = "jz" };

            Mapper.Map<Name, NameDto>(name13, nameDto13);

            //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

            Console.WriteLine("");

            Console.WriteLine(nameDto13.FirstName + nameDto13.LastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //14.Flatten特性 Store.Name.FirtName=FlattenName.NameFirstname

            Mapper.Reset();

            Mapper.CreateMap<Store, FlattenName>();

            Store store2 = new Store() { Name = new Name() { FirstName = "L", LastName = "jz" } };

            FlattenName nameDto14 = Mapper.Map<Store, FlattenName>(store2);

            Console.WriteLine("");

            Console.WriteLine(nameDto14.NameFirstname + nameDto14.NameLastName);

            Console.WriteLine();

            //Console.ReadKey();  

            //15.将Dictionary转化为对象,现在还不支持

            Mapper.Reset();

            Mapper.CreateMap<Dictionary<string, object>, Name>();

            Dictionary<string, object> dict = new Dictionary<string, object>();

            dict.Add("FirstName", "L");

            //Name name15 = Mapper.DynamicMap<Dictionary<string, object>, Name>(dict);

            Name name15 = Mapper.Map<Dictionary<string, object>, Name>(dict);

            Console.WriteLine("");

            Console.WriteLine(name15.FirstName);

            Console.WriteLine();

            Console.ReadKey();

        }

    }  

    public class Store

    {

        public Name Name { get; set; }

        public int Age { get; set; }

    }  

    public class Name

    {

        public string FirstName { get; set; }

        public string LastName { get; set; }

    }  

    public class StoreDto

    {

        public NameDto Name { get; set; }

        public int Age { get; set; }

    }  

    public class NameDto

    {

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string AllName { get; set; }

    }  

    public class FlattenName

    {

        public string NameFirstname { get; set; }

        public string NameLastName { get; set; }

    }  

    public class NameConverter : TypeConverter<Name, NameDto>

    {

        protected override NameDto ConvertCore(Name source)

        {

            return new NameDto() { AllName = source.FirstName + source.LastName };

        }

    }  

    public class NameResolver : ValueResolver<Name, NameDto>

    {

        protected override NameDto ResolveCore(Name source)

        {

            return new NameDto() { FirstName = source.FirstName, LastName = source.LastName,AllName=source.FirstName+source.LastName };

        }

    }  

    public class NameFormatter : ValueFormatter<NameDto>

    {

        protected override string FormatValueCore(NameDto name)

        {

            return name.FirstName + name.LastName;

        }

    }  

    public class StringFormatter : ValueFormatter<string>

    {

        protected override string FormatValueCore(string name)

        {

            return name + "-";

        }

    }

}

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