一、使用委托对List<>进行排序

现有类A，含三个属性，分别是NO，AGE，NAME，现在要求按照这个顺序排序（既先比较NO，如果相同比较AGE，如果AGE相同就比较NAME）。

类A的代码：

1: class A

2: {

3:     private string _name;

4:     public string NAME

5:     {

6:         get { return _name; }

7:         set { _name = value; }

8:     }

9: 

10:     private int _age;

11:     public int AGE

12:     {

13:         get { return _age; }

14:         set { _age = value; }

15:     }

16: 

17:     private int _no;

18:     public int NO

19:     {

20:         get { return _no; }

21:         set { _no = value; }

22:     }

23: 

24:     public A(int no, int age, string name)

25:     {

26:         this.NO = no;

27:         this.AGE = age;

28:         this.NAME = name;

29:     }

30: }

构造相应对象，对其进行排序测试：

1: static void Main(string[] args)

2: {

3:     //构造数据

4:     List list = new List();

5:     list.Add(new A(20, 20, "00001"));

6:     list.Add(new A(18, 50, "00003"));

7:     list.Add(new A(20, 19, "00004"));

8:     list.Add(new A(21, 21, "00005"));

9:     list.Add(new A(19, 19, "00006"));

10:     list.Add(new A(99, 19, "00007"));

11:     list.Add(new A(19, 19, "00008"));

12:     list.Add(new A(38, 50, "00009"));

13: 

14:     //进行排序

15:     list.Sort(delegate(A a1, A a2)

16:     {

17:         if (a1.NO.CompareTo(a2.NO) != 0)

18:             return a1.NO.CompareTo(a2.NO);

19:         else if (a1.AGE.CompareTo(a2.AGE) != 0)

20:             return a1.AGE.CompareTo(a2.AGE);

21:         else

22:             return a1.NAME.CompareTo(a2.NAME);

23:     });

24: 

25:     //打印输出

26:     foreach (A a in list)

27:     {

28:         Console.WriteLine(a.NO + " " + a.AGE + " " + a.NAME);

29:     }

30: 

31:     Console.ReadLine();

32: }

 

其实这是用委托表示的方法对 List 的元素进行排序。内部实现则为QuickSort 算法。

详情可参考：

原文地址：

 

 

二、使用委托对List<>进行筛选

C#里 List 筛选是很简单的事情，不用自已写循环去遍历，利用.net的特性 list.FindAll 可以很方便的实现。

1: /// 

2: /// 根据匹配条件获得子列表

3: /// 

4: /// 

5: /// 
      

6: private List
      
        selectList(List
       
         list)
       
      

7: {

8:     string name = txtName.Text.Trim();

9:     string nation = txtNation.Text.Trim();

10: 

11:     return list.FindAll(delegate(BaseInfo info)

12:     {

13:         if ((string.IsNullOrEmpty(name) || info.Name.IndexOf(name) != -1) && (string.IsNullOrEmpty(nation) || info.Nation.IndexOf(nation) != -1))

14:         {

15:             return true;

16:         }

17:         else

18:         {

19:             return false;

20:         }

21:     });

22: }

 

1: /// 

2: /// 从列表中获得分页数据

3: /// 

4: /// 

5: /// 

6: /// 

7: /// 
      

8: private List
      
        getPageData(List
       
         list, int pageIndex, int pageSize)
       
      

9: {

10:     return list.FindAll(delegate(BaseInfo info)

11:     {

12:         int index = list.IndexOf(info);

13:         if (index >= (pageIndex - 1) * pageSize && index < pageIndex * pageSize)

14:         {

15:             return true;

16:         }

17:         else

18:         {

19:             return false;

20:         }

21:     });

22: }

原文地址：