使用lambda表达式进行对象结合的筛选操作

public class Person : BaseDomain
    {
        long _id;
        string firstName;
        string secondName;
        string comments;

        public Person()
        {}
            
        public Person(long id)
        {
            this._id = id;
        }
        public Person(long id,string firstName, string secondName)
        {
            this._id = id;
            this.firstName = firstName;
            this.secondName = secondName;
            comments = String.Empty;
        }
        public Person(long id,string firstName, string secondName, string comments)
            : this(id,firstName, secondName)
        {
            this.comments = comments;
        }
      
        public string FirstName
        {
            get { return firstName; }
            set { firstName = value; }
        }
        public string SecondName
        {
            get { return secondName; }
            set { secondName = value; }
        }
        public string Comments
        {
            get { return comments; }
            set { comments = value; }
        }
        public override string ToString()
        {
            return string.Format("FirstName: {0}	SecondName: {1}	Comment: {2}", this.firstName, this.secondName, this.comments);
        }
    }

上面是测试需要的简单类型：Person

    var list = new List<Person>(5);
    list.Add(new Person(1,"咬金","程","拿斧子砍人的那个家伙");
    list.Add(new Person(2,"咬金","程","拿斧子砍人的那个家伙");
    list.Add(new Person(3,"貂蝉","王","3技能很厉害哦");
    list.Add(new Person(4,"昭君","李","适合打团战");
    list.Add(new Person(5,"亚瑟","毛","狠狠厚的肉")；

    //进行去重操作，需要先引入linq引用"using System.Linq; "
    var result_list = list.GroupBy(obj=>obj.FirstName).Select(g=>g.First()).ToList();

    foreach(var item in result_list)
    {
        Console.WriteLine(item);
    }