Question

当出于某种原因使用Automappers IMemberValueResolver时，TDestMember始终为0或null，是否有任何想法？

      public class CustomResolver : IMemberValueResolver<object, object, int, int>
    {
        public int Resolve(object source, object destination, int sourceMember, int destinationMember, ResolutionContext context)
        {
            return 1;
        }
    }

我如何称呼它的一个例子：

   .ForMember(dest => dest.SortOrder,
    opt => opt.ResolveUsing<CustomResolver, int>(src => src.Id));

Answer 1

当您未将目标对象传递给Map时会发生这种情况。

Answer 2

假设您的地图看起来像这样：

CreateMap<Source, Destination>
    .ForMember(dest => dest.SortOrder)
         opt => opt.ResolveUsing<CustomResolver, int>(src => src.Id));

您的CustomResolver如下所示：

public class CustomResolver : IMemberValueResolver<Source, Destination, int, int>
{
     public int Resolve(Source source, Destination destination, int sourceMember, int destinationMember, ResolutionContext context)
     {
         return 1;
     }
}

TDestMember （destinationMember参数）将为null或解析器内的默认值，因为尚未映射。 sourceMember参数将是地图中的谓词（src => src.Id）的值。

通常，仅在需要在解析逻辑所需的谓词中传递特定值时才使用IMemberValueResolver<>。否则，如果只需要源对象和/或目标对象，则应使用IValueResolver<>。

Automapper CustomResolver IMemberValueResolver TDestMember始终为null

2 个答案: