如何使用linq从嵌套字典中选择所有值？

Question

我的Super属性是

public List<Test> Super { get; set; }

而我的Test课程是

public class Test
{
    public int Id { get; set; }

    public Dictionary<string, string> dict { get; set; }
}

如何从字典中选择键名称为"description"所有值

Answer 1

您可以使用SelectMany获取所有词典，例如：

var values = Super
    .SelectMany(s => s.dict)
    .Where(s => s.Key == "description")
    .Select(s => s.Value);

Answer 2

你可以做点什么

var dict = (from p in obj.Super
                   where p.dict != null && p.dict.ContainsKey(keyToCheck)
                   select p.dict[keyToCheck]);

完整代码：

    void Main()
    {
        string keyToCheck = "description";
        var obj = new Super1();
        var dict = (from p in obj.Super
                   where p.dict != null && p.dict.ContainsKey(keyToCheck)
                   select p.dict[keyToCheck]);
        Console.Write(dict);
    }

    public class Super1
    {
        public List<Test> Super { get; set; } = new List<Test>(){
            new Test(){ Id = 1, dict = new Dictionary<string,string>() {
                {"description","abc"},{"description1","1"},{"description2","2"},{"description3","3"}
            }},
            new Test(){ Id = 2, dict = new Dictionary<string,string>() {
                {"description","xyz"},{"description4","4"},{"description5","5"},{"description6","6"}
            }
        }};
    }

    public class Test
    {
        public int Id { get; set; }

        public Dictionary<string, string> dict { get; set; }
    }

输出：

abc 
xyz 

Answer 3

你可以试试

List<string> AllValues = new List<string>();
Super.ForEach(x => 
      {
         if(x.dict.ContainsKey("description")
         {
             AllValues.AddRange(x.dict["description"]);
         } 
      });