使用 Automapper 基于内置数据类型创建对象

Question

我有两个类命名为 ApprenticeshipDto 一个 Apprenticeship 如下所示

public class ApprenticeshipDto
{
    public int Id { get; set; }
    public string PersonFirstName { get; set; }
    public string PersonLastName { get; set; }
}

 public class Apprenticeship
 {
     public virtual int Id { get; set; }
     public Person Person { get; set; }      
 }

public class Person
{
    public  string FirstName { get; set; }
    public  string LastName { get; set; }  
}

这就是我尝试将 ApprenticeshipDto 映射到 Apprenticeship 的方式：

Mapper.CreateMap<ApprenticeshipDto, Apprenticeship>();

Apprenticeship a = Mapper.Map<Apprenticeship>(Apprdto);

问题是所有属性都已正确映射，但 Person 未正确映射。是否可以告诉 Automapper 创建 Person 属性并自动将 PersonFirstName 和 PersonLastName 分配给 Person 对象的 FirstName 和 LastName？

Answer 1

是的，可以通过使用 custom value resolver class 告诉 AutoMapper 将 DTO 属性映射到目标对象属性。解析器将 PersonFirstName 和 PersonLastName 属性映射到新的 Person 对象：

// create the resolver class 
// -> extract person info from DTO and return a new Person object
public class CustomResolver : ValueResolver<ApprenticeshipDto, Person>
{
    protected override Person ResolveCore(ApprenticeshipDto source)
    {
        return new Person
            {
                    FirstName = source.PersonFirstName,
                    LastName = source.PersonLastName
            };
    }
}

然后在映射之前在 AutoMapper 配置中使用新的自定义解析器 class：

Mapper.CreateMap<ApprenticeshipDto, Apprenticeship>();

var adto = new ApprenticeshipDto
{
    Id = 10,
    PersonFirstName = "John",
    PersonLastName = "Doe"
};
// configure custom mapping
Mapper.CreateMap<ApprenticeshipDto, Apprenticeship>()
    .ForMember(destination => destination.Person, opt => opt.ResolveUsing<CustomResolver>());
Apprenticeship a = Mapper.Map<Apprenticeship>(adto);
Console.WriteLine("{0} - {1} - {2}", a.Id, a.Person.FirstName, a.Person.LastName);

输出符合预期：

10 - John - Doe

使用 Automapper 基于内置数据类型创建对象

Make an object base on built-in data types with Automapper

c#

automapper