您希望如何指定忽略某些成员?是否有您想要应用的约定、基类或属性?一旦您开始显式地指定所有映射，我不确定您能从AutoMapper中得到什么价值。

我已经更新了Can Gencer的扩展，不覆盖任何现有的地图。

public static IMappingExpression<TSource, TDestination> 
    IgnoreAllNonExisting<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
{
    var sourceType = typeof (TSource);
    var destinationType = typeof (TDestination);
    var existingMaps = Mapper.GetAllTypeMaps().First(x => x.SourceType.Equals(sourceType) && x.DestinationType.Equals(destinationType));
    foreach (var property in existingMaps.GetUnmappedPropertyNames())
    {
        expression.ForMember(property, opt => opt.Ignore());
    }
    return expression;
}

用法:

Mapper.CreateMap<SourceType, DestinationType>()
                .ForMember(prop => x.Property, opt => opt.MapFrom(src => src.OtherProperty))
                .IgnoreAllNonExisting();

更新:注意，在9.0版本Mapper静态API被删除

在dotnet 5的WebApi中，使用Nuget包automapper . extensions .微软。DependencyInjection，我在一个映射器配置文件中这样做。我对AutoMapper真的生疏了，但它现在似乎对未映射的成员工作得很好。

在启动:

var mapperConfig = new MapperConfiguration(mc => mc.AddProfile(new AutoMapperProfile()));
    services.AddSingleton(mapperConfig.CreateMapper());

在我的AutoMapperProfile中:

CreateMap<ProjectActivity, Activity>()
        .ForMember(dest => dest.ActivityName, opt => opt.MapFrom(src => src.Name))
        .ValidateMemberList(MemberList.None);

当前(版本9)忽略目标类型中不存在的属性的解决方案是创建一个翻转映射并反转它:

var config = new MapperConfiguration(cfg => {
  cfg.CreateMap<TheActualDestinationType, TheActualSourceType>().ReverseMap();
});

版本12 这是一个非常糟糕的代码，但它解决了紧急工作。

      CreateMap<RepairPutRequest, Repair>(MemberList.None) 
                .ForAbdusselamMember(x => x.ClosedLostTimeId, y => y.MapFrom(z => z.ClosedLostTimeId))
                .ForAbdusselamMember(x => x.Explanation, y => y.MapFrom(z => z.Explanation)).IgnoreUnmapped()
                ; 

  public static class MappingExtensions
    {
        public static Dictionary<string, List<string>> list = new Dictionary<string, List<string>>();
        public static IMappingExpression<TSource, TDestination> IgnoreUnmapped<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
        {
             var sourceType = typeof(TSource);
            var destinationType = typeof(TDestination);
            var key =$"{sourceType.FullName}__||__{destinationType.FullName}"   ;
            var t = list[key];
            foreach (var item in destinationType.GetProperties())
            {
                if (!t.Contains(item.Name)) {
                    expression.ForMember(item.Name, x => x.Ignore());
                    }
            }
            return expression;
        }
        public static IMappingExpression<TSource, TDestination> ForAbdusselamMember<TSource, TDestination, TMember>(this IMappingExpression<TSource, TDestination> expression,
            Expression<Func<TDestination, TMember>> destinationMember, Action<IMemberConfigurationExpression<TSource, TDestination, TMember>> memberOptions )
        {
            var sourceType = typeof(TSource);
            var destinationType = typeof(TDestination);
            var key = $"{sourceType.FullName}__||__{destinationType.FullName}";
            if (!list.ContainsKey(key))
            {
                list[key]=new List<string>();
            }
            expression.ForMember(destinationMember, memberOptions);
            var memberInfo = ReflectionHelper.FindProperty(destinationMember);

            list[key].Add(memberInfo.Name);
            return expression;
        }
          
    }

我已经能够做到这一点的方式如下:

Mapper.CreateMap<SourceType, DestinationType>().ForAllMembers(opt => opt.Ignore());
Mapper.CreateMap<SourceType, DestinationType>().ForMember(/*Do explicit mapping 1 here*/);
Mapper.CreateMap<SourceType, DestinationType>().ForMember(/*Do explicit mapping 2 here*/);
...

注意:我使用的是AutoMapper v.2.0。