从字典中的值列表中获取最大日期

Question

我找不到优雅的Linq方法来检索分配给人员列表中某人的最大日期，该人员被分配到任务中。

我的代码是

public class Mission 
{ 
    public string MissonAssignedTo { get; set; } 
    public DateTime Date { get; set; } 
} 

public Dictionary<string, Dictionary<string, List<Mission>>> MissionList = 
    new Dictionary<string, Dictionary<string, List<Mission>>>(); 

我有这个词典用这种价值观

MissionList[0] Key = MissionImpossible 
      Value = count 1 
        Key=Sean 
        Value=count 7 
         [0] = date = 10/01/2017 
         [1] = date = 10/01/2016 
         [2] = date = 10/01/2017 
         [3] = date = 10/01/2018 
         [4] = date = 10/01/2015 
         [5] = date = 10/01/2014 
         [6] = date = 10/01/2013 

MissionList[1] Key = MissionImpossibleThePayPack 
      Value = count 1 
        Key=Connery 
        Value=count 4 
         [0] = date = 10/01/2017 
         [1] = date = 10/01/2019 
         [2] = date = 10/01/2017 
         [3] = date = 10/01/2018 

我需要检索字典的每个人，他的最大日期，像这样的。

dicoResult= { 
       {Sean,10/01/2018} , 
       {Connery,10/01/2019} 
      } 

此致敬礼。 Jolynice

Answer 1

虽然你的自定义类型看起来怪我，如果我明白你正确，则这应该给您预期的结果： -

var result = MissionList.SelectMany(x => x.Value) 
         .ToDictionary(x => x.Key, y => y.Value.Max(z => z.Date)); 

首先拼合你内心的字典，最后项目的结果到字典使用ToDictionary。

Sample Fiddle.