1using System;
 2using System.Data;
 3using System.Configuration;
 4using System.Web;
 5using System.Web.Security;
 6using System.Web.UI;
 7using System.Web.UI.WebControls;
 8using System.Web.UI.WebControls.WebParts;
 9using System.Web.UI.HtmlControls;
10
11/**//// <summary>
12/// randomCode 的摘要说明
13/// </summary>
14public class randomCode
15...{
16    public randomCode()
17    ...{
18        //
19        // TODO: 在此处添加构造函数逻辑
20        //
21    }
22    /**//// <summary>
23    /// 验证码
24    /// </summary>
25    /// <param name="n">验证码的个数</param>
26    /// <returns>返回生成的随机数</returns>
27    public string RandomNum(int n) //
28    ...{
29        string strchar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z";
30        string[] VcArray = strchar.Split(',');
31        string VNum = "";                    //
32        int temp = -1;                       //记录上次随机数值，尽量避免产生几个一样的随机数
33                                             //采用一个简单的算法以保证生成随机数的不同
34        Random rand = new Random();
35        for (int i = 1; i < n + 1; i++)
36        ...{
37            if (temp != -1)
38            ...{
39                rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
40            }
41            int t = rand.Next(61);
42            if (temp != -1 && temp == t)
43            ...{
44                return RandomNum(n);
45            }
46            temp = t;
47            VNum += VcArray[t];
48        }
49        return VNum;//返回生成的随机数
50    }
51}
52