实现List的多列排序

List的sort（）方法，只能实现简单数据的排序，如过List里面装的是对象，就必须要显示实现IComparer接口，才能排序，并且有时我们需要对一个对象进行多列排序，如学生按学号，成绩升序排列。在实现这个接口的时候，我们可以对多个字段排序，代码如下：

public class People { public string Sex { get; set; } public int Age { get; set; } public string Name { get; set; } } public class PeopleComparer : IComparer<People> { private bool bASC; public PeopleComparer(bool asceding) { bASC = asceding; } #region IComparer<Student> public int Compare(People x, People y) { if (!bASC) { //降序 People temp; temp = y; y = x; x = temp; } int flg = -1; flg = Comparer<string >.Default.Compare(x.Sex, y.Sex); if (flg == 0) { flg = Comparer<int>.Default.Compare(x.Age, y.Age); } if (flg == 0) { flg = Comparer<string>.Default.Compare(x.Name, y.Name); } return flg; } #endregion } private void button1_Click(object sender, EventArgs e) { List<People> lstPeople = new List<People>(); lstPeople.Add(new People{ Sex ="man", Age =40, Name ="name1"}); lstPeople.Add(new People { Sex = "woman", Age = 15, Name = "name11" }); lstPeople.Add(new People { Sex = "man", Age = 35, Name = "name4" }); lstPeople.Add(new People { Sex = "man", Age = 55, Name = "name3" }); lstPeople.Add(new People { Sex = "man", Age = 35, Name = "name5" }); lstPeople.Add(new People { Sex = "man", Age = 60, Name = "name2" }); lstPeople.Add(new People { Sex = "woman", Age = 27, Name = "name15" }); lstPeople.Add(new People { Sex = "woman", Age = 37, Name = "name14" }); lstPeople.Add(new People { Sex = "woman", Age = 27, Name = "name12" }); lstPeople.Add(new People { Sex = "woman", Age = 47, Name = "name13" }); System.Diagnostics.Debug.WriteLine("原始数据："); DispPeople(lstPeople); System.Diagnostics.Debug.WriteLine("升序排列："); PeopleComparer ascCompare = new PeopleComparer(true); lstPeople.Sort(ascCompare); DispPeople(lstPeople); System.Diagnostics.Debug.WriteLine("降序排列："); PeopleComparer descCompare = new PeopleComparer(false ); lstPeople.Sort(descCompare); DispPeople(lstPeople); } private void DispPeople(IEnumerable<People> peoples) { foreach (People p in peoples) { System.Reflection.PropertyInfo[] pInfos = p.GetType().GetProperties(System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public); string str = ""; foreach (System.Reflection.PropertyInfo pi in pInfos) { str += pi.Name + ":" + pi.GetValue(p, null).ToString().PadRight(10,' '); } System.Diagnostics.Debug.WriteLine(str); } }

代码实现了按人的性别，年龄，名字排序，可以实现升序和降序。

结果：

原始数据：Sex:man Age:40 Name:name1 Sex:woman Age:15 Name:name11 Sex:man Age:35 Name:name4 Sex:man Age:55 Name:name3 Sex:man Age:35 Name:name5 Sex:man Age:60 Name:name2 Sex:woman Age:27 Name:name15 Sex:woman Age:37 Name:name14 Sex:woman Age:27 Name:name12 Sex:woman Age:47 Name:name13 升序排列：Sex:man Age:35 Name:name4 Sex:man Age:35 Name:name5 Sex:man Age:40 Name:name1 Sex:man Age:55 Name:name3 Sex:man Age:60 Name:name2 Sex:woman Age:15 Name:name11 Sex:woman Age:27 Name:name12 Sex:woman Age:27 Name:name15 Sex:woman Age:37 Name:name14 Sex:woman Age:47 Name:name13 降序排列：Sex:woman Age:47 Name:name13 Sex:woman Age:37 Name:name14 Sex:woman Age:27 Name:name15 Sex:woman Age:27 Name:name12 Sex:woman Age:15 Name:name11 Sex:man Age:60 Name:name2 Sex:man Age:55 Name:name3 Sex:man Age:40 Name:name1 Sex:man Age:35 Name:name5 Sex:man Age:35 Name:name4