C#Lambda-获取不同的Id并附加其他字段值

我有一个ID和标题列表，如下所示：

    List<Event> events= new List<Event>();

    events.Add(new Event(){ Id= "1001", Title= "abc" });
    events.Add(new Event(){ Id= "1002", Title= "xyz" });
    events.Add(new Event(){ Id= "1001", Title= "hij" });
    events.Add(new Event(){ Id= "1002", Title= "opq" });
    events.Add(new Event(){ Id= "1003", Title= "efg" });

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您能告诉我如何使用

C#Lambda表达式

实现这一点吗。提前感谢

您可以使用

GroupBy

+

String。加入

var query = events.GroupBy(x => x.Id)
    .Select(g => new Event 
     { 
         Id = g.Key, 
         Title = String.Join(",", g.Select(x => x.Title)) 
     });

如果需要新列表，请附加
.ToList（）

var query = events.GroupBy(x => x.Id)
    .Select(g => new Event 
     { 
         Id = g.Key, 
         Title = String.Join(",", g.Select(x => x.Title)) 
     });