List的排序

方法一、sort()

（1）当list中存的是简单数据类型时；

      public void Sort();

List<int> a = new List<int>() { 4, 5, 1, 2, 10, 78, 12, 5 }; a.Sort();//默认升序 foreach (var t in a) { Console.WriteLine(t); } Console.ReadKey();

 

（2）当list中存的是自定义数据类型时；

      public void Sort(Comparison<T> comparison);

      其中参数Comparison<T>委托的定义为：

      public delegate int Comparison<in T>(T x, T y)；

/// <summary> /// 定义一个数据类型 /// </summary> public class Student { public int ID { set; get; } public string Name { set; get; } public static List<Student> GetStudents() { List<Student> stu = new List<Student>(); List<int> a = new List<int>() { 4, 5, 1, 2, 10, 78, 12, 5 }; foreach (int t in a) { stu.Add(new Student { ID = t,Name="编号为"+ t +"的学生"}); } return stu; } }

           //排序，sort方法参数lambda表达式，根据学生ID排序 List<Student> stus = Student.GetStudents(); stus.Sort((item1, item2) => { if (item1.ID > item2.ID) { return 1;//升序，-1降序  } else if (item1.ID < item2.ID) { return -1; } else { return 0; } }); stus.ForEach(item => Console.WriteLine(item.ID + System.Environment.NewLine + item.Name)); Console.ReadKey();

方法二、OrderBy()

public static IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector);

            List<Student> stus = Student.GetStudents();
            //升序，降序OrderByDescending stus = stus.OrderBy(item => { return item.ID; }).ToList(); stus.ForEach(item => Console.WriteLine(item.ID + System.Environment.NewLine + item.Name)); Console.ReadKey();

结果：