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("1");  
            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("2");  
            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("3");  
            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("4");  
            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("5");  
            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("6");  
            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("7");  
            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("8");  
            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("9");  
            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("10");  
            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("11");  
            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("12");  
            Console.WriteLine(nameDto12[0].FirstName + nameDto12[0].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("13");  
            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("14");  
            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("15");  
            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 + "-";  
        }  
    }  
}