AutoMapper将属性设置为目标对象上的null

Question

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; }
}

并遵循映射器配置：

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());

要从DomainEntity获取ApiEntity，我使用var apiEntity = Mapper.Map<DomainEntity, ApiEntity>(myDomainEntity);

要从ApiEntity获取合并的DomainEntity，我使用var domainEntity = Mapper.Map(myApiEntity, myDomainEntity);

但是在使用它时，属性OtherEntities和AnotherEntities被设置为null - 即使它们在调用从myApiEntity到myDomainEntity的映射之前有值。 我怎样才能避免这种情况，以便它们真正融合而不仅仅是取代价值？

谢谢你的帮助。

Answer 1

我想你正在寻找UseDestinationValue而不是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());