抽牌式随机数序列

 1/**//// <summary>
 2    /// 生成4位随机数
 3    /// </summary>
 4    public class RandomNumber
 5    {
 6        private static int[] numberList;
 7        private static RandomNumber randomNumber;
 8        private RandomNumber()
 9        {
10            numberList = new int[9000];
11            for (int i = 0; i < 9000; i++)
12            {
13                numberList[i] = (i + 1000);
14            }
15        }
16        public static RandomNumber Run()
17        {
18            if (randomNumber == null || numberList == null)
19            {
20                randomNumber = new RandomNumber();
21            }
22            return randomNumber;
23        } 
24
25        private static int index = 8999;
26        public int GetRandomNumber()
27        {
28            Random rnd = new Random(unchecked((int)DateTime.Now.Ticks)); 
29
30            int i = rnd.Next(0, index + 1); //抽取的序列号 
31
32            int r = numberList[i]; 
33
34            int t = numberList[index];
35            numberList[index] = numberList[i];
36            numberList[i] = t; 
37
38            index--;
39            if (index <= 0)
40            {
41                index = 8999;
42            }
43            return r;
44        }
45
46

只是为了防止重复出现而已... 但是还是会有重复的出现..囧..

原因在web上如果同时N个人运行到此程序,则有可能出现相同的数字