ラムダ式を使ったオブジェクト結合演算例を詳しく解説

1publicclass Person : BaseDomain
 2    {
 3long _id;
 4string firstName;
 5string secondName;
 6string comments;
 7 8public Person()
 9        {}
1011public Person(long id)
12        {
13this._id = id;
14        }
15public Person(long id,string firstName, string secondName)
16        {
17this._id = id;
18this.firstName = firstName;
19this.secondName = secondName;
20             comments = String.Empty;
21        }
22public Person(long id,string firstName, string secondName, string comments)
23             : this(id,firstName, secondName)
24        {
25this.comments = comments;
26        }
2728publicstring FirstName
29        {
30get { return firstName; }
31set { firstName = value; }
32        }
33publicstring SecondName
34        {
35get { return secondName; }
36set { secondName = value; }
37        }
38publicstring Comments
39        {
40get { return comments; }
41set { comments = value; }
42        }
43publicoverridestring ToString()
44        {
45returnstring.Format("FirstName: {0}\tSecondName: {1}\tComment: {2}", this.firstName, this.secondName, this.comments);
46        }
47     }

1var list = new List<Person>(5);
 2     list.Add(new Person(1,"咬金","程","拿斧子砍人的那个家伙");
 3     list.Add(new Person(2,"咬金","程","拿斧子砍人的那个家伙");
 4     list.Add(new Person(3,"貂蝉","王","3技能很厉害哦");
 5     list.Add(new Person(4,"昭君","李","适合打团战");
 6     list.Add(new Person(5,"亚瑟","毛","狠狠厚的肉")；
 7 8//进行去重操作，需要先引入linq引用"using System.Linq; " 9var result_list = list.GroupBy(obj=>obj.FirstName).Select(g=>g.First()).ToList();
1011foreach(var item in result_list)
12    {
13        Console.WriteLine(item);
14     }