C# 如何使用linq从嵌套字典中选择所有值？

我的

Super

类属性为

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

---

如何从关键字名称为“description”的字典中选择所有值？您可以使用

SelectMany

获取所有字典，例如：

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

你可以试试

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

List AllValues=new List（）；
Super.ForEach（x=>
{
如果（x.dict.ContainsKey（“说明”）
{
AllValues.AddRange（x.dict[“description”]）；
} 
});

您可以执行以下操作

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; }
    }

---

不过，混合使用Linq fluent和查询语法有点尴尬。从lambdata中删除此操作不使用字典的O（1）查找。

    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; }
    }

abc 
xyz