Automapper 链/嵌套对象映射抛出异常

Posted 2023-03-27

【中文标题】Automapper 链/嵌套对象映射抛出异常

【英文标题】：Automapper chain / nested object mapping throw exception

【发布时间】：2021-11-06 00:29:23

【问题描述】：

我在 .NET CORE 5 项目中使用 AutoMapper 版本 10.1.1。我有嵌套的对象，我需要映射但无法这样做并得到以下异常，尽管我可以为第一个孩子映射数据，在我的情况下为“强制”但无法访问子对象“违规”的孩子

0 级课程

 public class SiteContraventionDataView

    public int SiteId  get; set; 

    public string SiteName  get; set; 

    public ICollection<EnforcementDataView> Enforcements  get; set; 

1 级儿童班

public class EnforcementDataView

    public int EnforcementId  get; set; 

    public ICollection<ContraventionDataView> Contraventions  get; set; 

当我尝试从上面的子类设置“Contraventions”的来源时出现错误。我正在尝试使用 lambda 表达式来获取 Contravention 对象引用

 .ForMember(dataView => dataView.Enforcements.Select(x=>x.Contraventions), opt => opt.MapFrom(dataModel => GetContraventions(dataModel.Enforcements.ToList())))

自动映射类

public class SiteContraventionsProfile : Profile

    public SiteContraventionsProfile()
    
        CreateMap<Site, SiteContraventionDataView>()
            .ForMember(dataView => dataView.SiteId, opt => opt.MapFrom(dataModel => dataModel.SiteId))
            .ForMember(dataView => dataView.SiteName, opt => opt.MapFrom(dataModel => dataModel.SiteName))
            .ForMember(dataView => dataView.Enforcements, opt => opt.MapFrom(dataModel => dataModel.Enforcements))
            .ForMember(dataView => dataView.Enforcements.Select(x=>x.Contraventions), opt => opt.MapFrom(dataModel => GetContraventions(dataModel.Enforcements.ToList())))
            ;

       
    

    private List<Contravention> GetContraventions(List<Enforcement> enforcements)
    
        List<Contravention> contraventions = new List<Contravention>();

        if (enforcements.Any())
        
            var t1 = enforcements.Select(x => x.EnforcementContraventions);
        
        
        return contraventions;
    

【参考方案1】：

尝试为Enforcement 和Contravention 添加映射：

CreateMap<Enforcement, EnforcementDataView>();
CreateMap<Contravention, ContraventionDataView>();
CreateMap<Site, SiteContraventionDataView>();