C# List<>.sort 排序【转载】

转载：http://hi.baidu.com/lifangfang1218/blog/item/aa49002362f76bf9d6cae244.html

第三种方法需要编写一个对象排序比较的方法，对List中的元素对象没有特殊的要求，但在比较方法中需要实现对象比较规则，这个方法实现后，就可以把这方 名字作为参数委托给List的Sort方法，Sort方法在排序时会执行这个方法对List中的对象进行比较，详细可参照下面的代码。对List中元素我 们还使用上面的SortTestObj2类对象。

1.         staticvoid Main(string[] args)
2.          {
3.             //利用代理方法进行排序
4.              DelegateSort();
5.          }
6.         
7.         //Sort(Comparison<(Of <(T>)>))方法排序,这中方法需要先编写一个对象比较的方法,然后
8.         //把这个比较方法委托给List的Sort方法。
9.         //对象比较的方法
10.         privatestaticint SortTestObj2Compare(SortTestObj2 obj1, SortTestObj2 obj2)
11.          {
12.             int res = 0;
13.             if ((obj1 == null) && (obj2 == null))
14.              {
15.                 return 0;
16.              }
17.             elseif ((obj1 != null) && (obj2 == null))
18.              {
19.                 return 1;
20.              }
21.             elseif ((obj1 == null) && (obj2 != null))
22.              {
23.                 return -1;
24.              }
25.             if (obj1.Code > obj2.Code)
26.              {
27.                  res = 1;
28.              }
29.             elseif (obj1.Code < obj2.Code)
30.              {
31.                  res = -1;
32.              }
33.       //如果是时间类型的比较，我现在写的是倒序，如果想正序把1改为-1，-1改为1
34.        if (DateTime.Parse(obj1.MailDate).CompareTo(DateTime.Parse(obj2.MailDate))>0)
                {
                res = -1;
                    }
                else if (DateTime.Parse(obj1.MailDate).CompareTo(DateTime.Parse(obj2.MailDate)) < 0)
                {
                res = 1;
                 }
35.        
36.    //如果是string类型的比较，我现在写的是倒序，如果想正序把1改为-1，-1改为1
37. //if (obj1.MailDate.CompareTo(obj2.MailDate) > 0)
                //    {
                //    res = -1;
                //    }
                //else if (obj1.MailDate.CompareTo(obj2.MailDate) < 0)
                //    {
                //    res = 1;
                //    }        
38.             return res;
39.          }
40.         //List的委托排序
41.         privatestaticvoid DelegateSort()
42.          {
43.              List<SortTestObj2> objLst = new List<SortTestObj2>();
44.              SortTestObj2 obj1 = new SortTestObj2();
45.              obj1.Code = 3;
46.              obj1.Name = "TestObj1";
47.              objLst.Add(obj1);
48.              SortTestObj2 obj2 = new SortTestObj2();
49.              obj2.Code = 2;
50.              obj2.Name = "TestObj2";
51.              objLst.Add(obj2);
52.              SortTestObj2 obj3 = new SortTestObj2();
53.              obj3.Code = 4;
54.              obj3.Name = "TestObj4";
55.              objLst.Add(obj3);
56.              SortTestObj2 obj4 = new SortTestObj2();
57.              obj4.Code = 1;
58.              obj4.Name = "TestObj3";
59.              objLst.Add(obj4);
60.              SortTestObj2 obj5 = new SortTestObj2();
61.              obj5.Code = 6;
62.              obj5.Name = "TestObj6";
63.              objLst.Add(obj5);
64.              objLst.Sort(SortTestObj2Compare);
65.              Console.WriteLine("委托方法排序的结果");
66.             foreach (SortTestObj2 item in objLst)
67.              {
68.                  Console.WriteLine("Code=" + item.Code + ",Name=" + item.Name);
69.              }
70.          }