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 + "-";
        }
    }
}