C# 自定义类排序

1）声明一个类

/// <summary>
/// 人物类
/// </summary>
public class Person
{
  public string Name;
  public int Age;
  public override string ToString()
  {
    return "Name: " + Name + " Age: " + Age;
  }
}

2）声明一个继承了接口IComparer的类

/// <summary>
/// 比较人物类实例大小，实现接口IComparer
/// </summary>
public class PersonComparer : IComparer<Person>
{
  public int Compare(Person x, Person y)
  {
    if (x == null && y == null) return 0;
    if (x == null) return -1;
    if (y == null) return 1;
    //TODO：Person类实例X与Y的比较规则
    //按姓名由小到大排列，姓名相同的人年龄大的在前
    {
      int temp = string.Compare(x.Name, y.Name);
      if (temp > 0) return -1;
      else if (temp < 0) return 1;
      if (x.Age > y.Age) return 1;
      if (x.Age < y.Age) return -1;
    }
    return 0;
  }
}

3）Main函数，建立一个List，并使用刚建立的PersonComparer类中的规则对List进行排序

static void Main(string[] args)
{
  List<Person> a = new List<Person>();
  a.Add(new Person() { Name = "Tsybius", Age = 23 });
  a.Add(new Person() { Name = "Galatea", Age = 21 });
  a.Add(new Person() { Name = "Lucius", Age = 22 });
  a.Add(new Person() { Name = "Septimus", Age = 22 });
  a.Add(new Person() { Name = "Octavius", Age = 22 });
  a.Add(new Person() { Name = "Lucius", Age = 24 });
  //输出a中全部元素
  Console.WriteLine("排序前");
  foreach (var v in a)
  {
    Console.WriteLine(v.ToString());
  }
  Console.WriteLine("-");
  //对a进行排序
  a.Sort(new PersonComparer());
  //输出a中全部元素
  Console.WriteLine("排序后");
  foreach (var v in a)
  {
    Console.WriteLine(v.ToString());
  }
  Console.WriteLine("-");
  Console.ReadLine();
}