使用 Automapper 将一个类实例映射到另一个类的列表

Posted 2023-03-17

【中文标题】使用 Automapper 将一个类实例映射到另一个类的列表

【英文标题】：Map a class instance to a list of another class with Automapper

【发布时间】：2020-02-12 05:39:36

【问题描述】：

是否可以将AddToClientCommand 映射到List<AddToClient> ？

public class AddToClientCommand : IRequest<AddToClientResponse>

    public List<int> AccountIds  get; set;  
    public int ClientId  get; set; 


public class AddToClient

    public int AccountId  get; set; 
    public int ClientId  get; set; 

达到以下效果：

var command = new AddToClientCommand

    AccountIds = new List<int>  1, 2 ,
    ClientId = 42
;

var result = // somehow automap with Automapper

var expected = new List<AddToClient>

    new AddToClient  AccountId = 1, ClientId = 42 ,
    new AddToClient  AccountId = 2, ClientId = 42 
;

expected.Should().BeEquivalentTo(result);

【参考方案1】：

这里不需要使用 AutoMapper。 你可以用 Linq 查询做你想做的事

var expected = command.AccountIds.Select(id => new AddToClient  AccountId = id, ClientId = command.ClientId ).ToList();

【参考方案2】：

AutoMapper ： 据我了解，将AddToClientCommand 映射到List<AddToClient> 是不可能的。因为 AotuMapper 提供了 2 种映射方式，如下...

例如：我们有 Employee 和 User 等 2 个类

    public class Employee  
  
    public int EmployeeId  get; set;   
    public string EmployeeFName  get; set;   
    public string EmployeeLName  get; set;   
    public string Address  get; set;   
    public string City  get; set;   
    public string State  get; set;   
    public string Zip  get; set;   
    public DateTime? DateOfJoining  get; set;     


public class User  
  
    public int Userid  get; set;   
    public string UserFName  get; set;   
    public string UserLName  get; set;   
    public string Address  get; set;   
    public string City  get; set;   
    public string State  get; set;   
    public string Zip  get; set;   
    public DateTime? DateOfJoining  get; set;   

  

Employee objEmployee = new Employee  
   
    EmployeeId = 1001,  
    EmployeeFName = "Manish",  
    EmployeeLName = "Kumar",  
    Address = "JAIPUR",  
    City = "JAIPUR",  
    State = "RAJASTHAN",  
    Zip = "302004",  
    DateOfJoining = DateTime.Now,  
 ;  

//1.如果属性相同，则创建地图并复制所有字段

Mapper.CreateMap<Employee, User>(); 

//2.如果属性不同，我们需要将员工的字段映射到用户的字段，如下所示。

 AutoMapper.Mapper.CreateMap<Employee, User>()  
 .ForMember(o => o.Userid, b => b.MapFrom(z => z.EmployeeId))  
 .ForMember(o => o.UserFName, b => b.MapFrom(z => z.EmployeeFName))  
 .ForMember(o => o.UserLName, b => b.MapFrom(z => z.EmployeeLName));  

 User objuser = Mapper.Map<Employee, User>(objEmployee);

// 但是您的要求将通过 Linq Query 来满足...

  AddToClientCommand addCommand = new AddToClientCommand
   
       AccountIds = new List<int>  1, 2 ,
       ClientId = 42
   ; 

   List<AddToClient> addClientList = addCommand.AccountIds.Select(item => new AddToClient  AccountId = item, ClientId = addCommand.ClientId ).ToList();

输出：

【讨论】：

谢谢，我知道可以用 LINQ 完成。我只是想知道Automapper是否有可能