Question

我有类似于下面的主题的类定义与子项，它可以深入三级。我想要的是匹配项的直接父（作为列表/集合）。下面的代码将获得我想要的结果，但我必须使用2个步骤。我怎么能一步到位呢。

C＃代码。

      string id = 'edf23fb667f5';
       var topics = GetTopics(); //Get the data from DB with childre
       var topic = topics.FirstOrDefault(x => x.Children.Any(y => y.Id == id)); //First level match
 var subTopic = topic?.Children.FirstOrDefault(y => y.Id == id); //Second level match

public class Topic
{
   public string Id;
   public string Name;
   public List<Topic> Children;
}

我的样本json如下所示

[
  {
    "Id": "5174daff0f78",
    "Name": "First Level",
    "Children": [
      {
        "Id": "9ea17d89bc60",
        "Name": "Second Level",
        "Children": [
          {
            "Id": "afb2a0cd3bd9",
            "Name": "Third Level 1",
            "Children": []
          },
          {
            "Id": "edf23fb667f5",
            "Name": "Third Level 2",
            "Children": []
          },
          {
            "Id": "506b4cd4922b",
            "Name": "Third Level 3",
            "Children": []
          }
        ]
      }
    ]
  }
]

Answer 1

        string id = "edf23fb667f5";
        var topics = GetTopics();
        var subTopic = topics.FirstOrDefault(x => x.Children.Any(y => y.Id == id))
        .Children.FirstOrDefault(s => s.Id == id);

Linq / lambda获取匹配子记录的直接父级（三级对象）

1 个答案: