AutoMapper设置属性为null目标对象上 [英] AutoMapper settings properties to null on destination object

问题描述

我有这样的事情：

public class DomainEntity
{
    public string Name { get; set; }
    public string Street { get; set; }
    public IEnumerable<DomainOtherEntity> OtherEntities { get; set; }
    public IEnumerable<DomainAnotherEntity> AnotherEntities { get; set; }
}

public class ApiEntity
{
    public string Name { get; set; }
    public string Street { get; set; }
    public int OtherEntitiesCount { get; set; }
}

和下面的映射配置：

Mapper.Configuration.AllowNullCollections = true;

Mapper.CreateMap<DomainEntity, ApiEntity>().
    ForSourceMember(e => e.OtherEntities, opt => opt.Ignore()).
    ForSourceMember(e => e.AntherEntities, opt => opt.Ignore()).
    ForMember(e => e.OtherEntitiesCount, opt => opt.MapFrom(src => src.OtherEntities.Count()));

Mapper.CreateMap<ApiEntity, DomainEntity>().
    ForSourceMember(e => e.OtherEntitiesCount, opt => opt.Ignore()).
    ForMember(e => e.OtherEntities, opt => opt.Ignore()).
    ForMember(e => e.AnotherEntities, opt => opt.Ignore());

要获得我用从DomainEntity的ApiEntity VAR apiEntity =映射.MAP< DomainEntity，ApiEntity>（myDomainEntity）;

To get the ApiEntity from the DomainEntity I'm using var apiEntity = Mapper.Map<DomainEntity, ApiEntity>(myDomainEntity);

要从我使用的是ApiEntity获得合并DomainEntity VAR domainEntity = Mapper.Map（myApiEntity，myDomainEntity）;

To get the merged DomainEntity from an ApiEntity I'm using var domainEntity = Mapper.Map(myApiEntity, myDomainEntity);

但是，当使用此，属性 OtherEntities 和 AnotherEntities 设置为空 - 甚至当他们呼吁从映射之前有值 myApiEntity 到 myDomainEntity 。我怎样才能避免这种情况，使他们真正的合并并不仅仅是更换价值？

But when using this, the properties OtherEntities and AnotherEntities are set to null - even when they had values before calling the mapping from myApiEntity to myDomainEntity. How can I avoid this so they really merge and not just replacing values?

感谢您的帮助。

推荐答案

我认为你正在寻找 UseDestinationValue 而不是忽略：

I think you're looking for UseDestinationValue instead of Ignore:

Mapper.CreateMap<ApiEntity, DomainEntity>().
    ForSourceMember(e => e.OtherEntitiesCount, opt => opt.UseDestinationValue()).
    ForMember(e => e.OtherEntities, opt => opt.UseDestinationValue()).
    ForMember(e => e.AnotherEntities, opt => opt.UseDestinationValue());

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