当前文件路径：DaDaNews/Admin/Validata.aspx.cs

		            
 1using System;
 2using System.Data;
 3using System.Configuration;
 4using System.Collections;
 5using System.Web;
 6using System.Web.Security;
 7using System.Web.UI;
 8using System.Web.UI.WebControls;
 9using System.Web.UI.WebControls.WebParts;
10using System.Web.UI.HtmlControls;
11using System.Drawing;
12using System.Drawing.Imaging;
13
14public partial class Validata : System.Web.UI.Page
15...{
16    protected void Page_Load(object sender, EventArgs e)
17    ...{
18        Session["code"] = RandNum(4);
19        ValidateCode(Session["code"].ToString(), 40, 20, "黑体", 10, "#FFFFFF");        
20    }
21
22    /**//// <summary>
23    /// 该方法用于生成指定位数的随机数
24    /// </summary>
25    /// <param name="VcodeNum">参数是随机数的位数</param>
26    /// <returns>返回一个随机数字符串</returns>
27    private string RandNum(int VcodeNum)
28    ...{
29        string Vchar = "0,1,2,3,4,5,6,7,8,9";
30        string[] VcArray = Vchar.Split(',');//拆分成数组
31        string VNum = "";
32        int temp = -1;//记录上次随机数值，尽量避避免生产几个一样的随机数
33
34        Random rand = new Random();
35        //采用一个简单的算法以保证生成随机数的不同
36        for (int i = 0; i < VcodeNum; i++)
37        ...{
38            if (temp != -1)
39            ...{
40                rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
41            }
42
43            int t = rand.Next(VcArray.Length - 1);
44            if (temp != -1 && temp == t)
45            ...{
46                return RandNum(VcodeNum);
47
48            }
49            temp = t;
50            VNum += VcArray[t];
51        }
52        return VNum;
53    }
54
55    /**//// <summary>
56    /// 生成图片并写入字符
57    /// </summary>
58    /// <param name="VNum">目标字符</param>
59    /// <param name="w">宽</param>
60    /// <param name="h">高</param>
61    /// <param name="font">字体文件</param>
62    /// <param name="fontSize">字体大小</param>
63    /// <param name="bgColor">图片背景颜色</param>
64    private void ValidateCode(string VNum, int w, int h, string font, int fontSize, string bgColor)
65    ...{
66        Bitmap Img = new Bitmap(w, h);//生成图像的实例
67        Graphics g = Graphics.FromImage(Img);//从Img对象生成新的Graphics对象
68        g.Clear(ColorTranslator.FromHtml(bgColor));//背景颜色
69        Font f = new Font(font, fontSize);//生成Font类的实例
70        SolidBrush s = new SolidBrush(Color.Black);//生成笔刷类的实例
71        g.DrawString(VNum, f, s, 3, 3);//将VNum写入图片中
72        Img.Save(Response.OutputStream, ImageFormat.Jpeg);//将此图像以Jpeg图像文件的格式保存到流中
73        Response.ContentType = "image/Jpeg";
74        //回收资源
75        g.Dispose();
76        Img.Dispose();
77        Response.End();
78    }
79
80}
81