Question

我有一个场景，我必须使用AutoMapper将DTO映射到域对象。这种映射需要一些复杂的管理，所以我创建了一个自定义值解析器。我想从Foo获取FooDTO。这两个对象之间的唯一区别是Foo具有ICollection<Child>而FooDTO具有TrackedData<ChildDTO>，其中TrackeData<T>是具有3 ICollection<T>的对象}。这是我的简化方案：

public class TrackedData<T>
{
    public ICollection<T> Updated { get; set; }
    public ICollection<T> Created { get; set; }
    public ICollection<T> Deleted { get; set; }

    public TrackedData()
    {
        Updated = new List<T>();
        Created = new List<T>();
        Deleted = new List<T>();
    }
}

public class Foo
{
    private List<Child> _childs;

    public string Name { get; set; }
    public ICollection<Child> Childs
    {
        get
        {
            if (_childs == null)
                _childs = new List<Child>();
            return _childs;
        }
        set
        {
            _childs = (List<Child>)value;
        }
    }
}

public class Child
{
    public string Description { get; set; }
}

public class FooDTO
{
    public string Name { get; set; }
    public TrackedData<ChildDTO> Childs { get; set; }
}

public class ChildDTO
{
    public string Description { get; set; }
}

public class Program
{
    public static void Main(string[] args)
    {
        Mapper.CreateMap(typeof(TrackedData<>), typeof(TrackedData<>));
        Mapper.CreateMap<ChildDTO, Child>();
        Mapper.CreateMap<FooDTO, Foo>()
            .ForMember(d => d.Childs, opt => opt.ResolveUsing<TrackedDataResolver<ChildDTO, Child>>());

        FooDTO fooDTO = CreateFakeFooDTO();

        Foo foo = Mapper.Map<FooDTO, Foo>(fooDTO);
    }

    private static FooDTO CreateFakeFooDTO() { /* omitted for simplicity */ }

    private static TrackedData<ChildDTO> CreateFakeTrackedDataChildDTO() { /* omitted for simplicity */ }

    private static ICollection<ChildDTO> CreateFakeListChildDTO() { /* omitted for simplicity */ }

    private static ChildDTO CrateFakeChildDTO(){ /* omitted for simplicity */ }
}

public class TrackedDataResolver<TSource, TDestination> : ValueResolver<TrackedData<TSource>, ICollection<TDestination>>
{
    protected override ICollection<TDestination> ResolveCore(TrackedData<TSource> source)
    {
        TrackedData<TDestination> trackedDestination = new TrackedData<TDestination>();
        ICollection<TDestination> destination = new List<TDestination>();

        trackedDestination = Mapper.Map<TrackedData<TSource>, TrackedData<TDestination>>(source);

        foreach (var o in trackedDestination.Created)
        {
            // Do stuff...
            destination.Add(o);
        }
        foreach (var o in trackedDestination.Updated)
        {
            // Do stuff...
            destination.Add(o);
        }
        foreach (var o in trackedDestination.Deleted)
        {
            // Do stuff...
            destination.Add(o);
        }

        return destination;
    }
}

执行此行时

Foo foo = Mapper.Map<FooDTO, Foo>(fooDTO);

我收到此错误：

{＆＃34;提供的值是AutoMapperDemo.FooDTO类型，但预计AutoMapperDemo.TrackedData＆＃39; 1 [AutoMapperDemo.ChildDTO]。更改值解析程序源类型，或使用FromMember重定向提供给值解析程序的源值。\ r \ n提供的值是AutoMapperDemo.FooDTO类型但预期AutoMapperDemo.TrackedData＆＃39; 1 [AutoMapperDemo.ChildDTO]。更改值解析程序源类型，或使用FromMember重定向提供给值解析器的源值。＆＃34;}

Source code在Github中可用：https://github.com/josmonver/AutoMapperValueResolverIssue.git 知道为什么我会收到这个错误吗？

Answer 1

您可以在UnionAll类中实现TrackedData<T>方法（已更新+已创建+已删除）并将其映射到

，而不是将重要逻辑带入映射器。

    Mapper.CreateMap<FooDTO, Foo>()
        .ForMember(d => d.Childs, opt => opt.MapFrom(src => src.UnionAll()));

AutoMapper Resolve使用泛型导致＆＃34;提供的值是X类型但是预期Y＆＃34;错误

1 个答案: