Automapper - 忽略有条件的映射

我正在使用自动映射器，我想知道当字段为空时是否可以忽略字段的映射。

这是我的代码：

.ForMember(dest => dest.BusinessGroup_Id, 
           opt => opt.MapFrom(src => (int)src.BusinessGroup))

• src.BusinessGroup type = "enum"
• dest.BusinessGroup_Id = int

目标是忽略 arc.Business Group = null 的映射。

I think NullSubstitute https://github.com/AutoMapper/AutoMapper/wiki/Null-substitution选项就能解决问题

.ForMember(d => d.BusinessGroup_Id, o => o.MapFrom(s => (int?)s.BusinessGroup));
.ForMember(d => d.BusinessGroup_Id, o => o.NullSubstitute(0));

顺便说一句，您可以在映射操作中写入您的条件：

.ForMember(d => d.BusinessGroup_Id,
           o => o.MapFrom(s => s.BusinessGroup == null ? 0 : (int)s.BusinessGroup));   

UPDATE如果您无法为属性分配一些默认值，则可以忽略它并仅映射非空值：

.ForMember(d => d.BusinessGroup_Id, o => o.Ignore())
.AfterMap((s, d) =>
    {
        if (s.BusinessGroup != null)
            d.BusinessGroup_Id = (int)s.BusinessGroup;
    });