AutoMapper设置属性设置为null目标对象

Question

对我有这样的事情：我使用var apiEntity = Mapper.Map<DomainEntity, ApiEntity>(myDomainEntity);

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()); 

要获得从DomainEntity的ApiEntity：

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; } 
} 

而继映射配置

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

但是当使用这个时，属性OtherEntities和AnotherEntities被设置为null - 即使它们在调用从myApiEntity到myDomainEntity的映射之前具有值。我怎样才能避免这个，所以他们真的合并而不只是更换值？

感谢您的任何帮助。

Answer 1

我认为你正在寻找的UseDestinationValue代替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());