如何使用AutoMapper映射目标对象和源对象中的子对象? [英] How to use AutoMapper to map destination object with a child object in the source object?

问题描述

我有这样的源对象和目标对象:

I have the source and destination objects like this:

class ProductWithCategories // Source class
{
    public Product Product { get; set; } // Product is an EF entity class
    public IEnumerable<Category> Categories { get; set; }
}

class ProductViewModel // Dest class
{
    public int Id { get; set; }
    // Other properties with the same name as Product class

    public IEnumerable<CategoryViewModel> Categories { get; set; }
}

所以，我需要将source.Product的值映射到dest，然后将source.Categories的值映射到dest.Categories.可以使用AutoMapper吗?

So, my need is to map the values of source.Product into dest, and then source.Categories into dest.Categories. Is it possible with AutoMapper?

我已经尝试过了，但是当它失败时我并不感到惊讶:

I have tried this and I was not surprised when it failed:

        config.CreateMap<ProductWithCategories, ProductViewModel>()
            .ForMember(q => q, option => option.MapFrom(q => q.Product))
            .ForMember(q => q.Categories, option => option.MapFrom(q => q.Categories));

这是我收到的例外情况:

Here is the exception I received:

[AutoMapperConfigurationException:成员的自定义配置为 仅支持类型上的顶级个人成员.]

[AutoMapperConfigurationException: Custom configuration for members is only supported for top-level individual members on a type.]

推荐答案

与OP进行了一些讨论之后，事实证明，他的主要需求是快速将源对象内部的子对象/嵌套对象映射到扁平化的目标对象.他不想为目的地的每个属性编写一个映射.

After some discussion with OP, it turns out his main need is to quickly map a child/nested object inside the source object to the flattened destination object. He does not want to write a mapping for every property of the destination.

这是实现此目标的一种方法:

Here is a way to achieve this:

• 定义用于展平Product成员的映射Product-> ProductViewModel
• 定义映射Category到CategoryViewModel

• 定义用于映射类别的映射ProductWithCategories-> ProductViewModel，然后在后映射中映射Product:

• Define a mapping Product -> ProductViewModel used to flatten the members of Product
• Define a mapping Category to CategoryViewModel

• Define a mapping ProductWithCategories -> ProductViewModel that maps the categories, and then in the aftermap, map the Product:

config.CreateMap<ProductWithCategories, ProductViewModel>() .ForMember(q => q.Id, option => option.Ignore()) // flattened in AfterMap .ForMember(q => q.Categories, option => option.MapFrom(q => q.Categories)) .AfterMap((src, dst) => Mapper.Map(src.Product, dst));

config.CreateMap<ProductWithCategories, ProductViewModel>() .ForMember(q => q.Id, option => option.Ignore()) // flattened in AfterMap .ForMember(q => q.Categories, option => option.MapFrom(q => q.Categories)) .AfterMap((src, dst) => Mapper.Map(src.Product, dst));

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