.net core 自动映射将嵌套对象集合展平为字符串集合

如何创建AutoMapper配置文件以映射多对多关系

我有三个实体-

Question

、

Tag

和

QuestionTag

class Question
{
   ICollection<QuestionTag> tags {get;set;}
}

class QuestionTag
{
   int questionId {get;set;}
   Question question {get;set;}

   int tagId {get;set;}
   Tag tag {get;set;}
}

class Tag {
   string name {get;set;}
}

如何配置automapper配置文件以映射此内容

下面的映射导致了一个错误，可能是因为我无法深入到

t.tag.name

CreateMap<Question, QuestionSummary>()
  .ForMember(x => x.tags, o => o.MapFrom(x => x.tags.Select(t => t.tag.name)));


System.InvalidCastException: Unable to cast object of type 'System.Linq.Expressions.NewExpression' to type 'System.Linq.Expressions.MethodCallExpression'.

重做会有帮助的。制定一个我们可以执行并看到失败的计划。

CreateMap<Question, QuestionSummary>()
  .ForMember(x => x.tags, o => o.MapFrom(x => x.tags.Select(t => t.tag.name)));


System.InvalidCastException: Unable to cast object of type 'System.Linq.Expressions.NewExpression' to type 'System.Linq.Expressions.MethodCallExpression'.

CreateMap<Tag, string>()
    .ConvertUsing(x => x.name);
CreateMap<ICollection<Tag>, ICollection<string>>()
    .ConvertUsing(x => x.Select(t => t.name).ToList());
CreateMap<Question, QuestionSummary>()
    .ForMember(x => x.tags, o => o.MapFrom(x => x.tags.Select(t => t.tag)));