C# 生成简单验证码_.NET_编程开发_程序员俱乐部

网站登录总是会用到验证码，生成验证码对于C#来说很简单。因为有专门封装好的GDI+类可以直接调用使用具体代码如下

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Web;
 5 using System.Web.UI;
 6 using System.Web.UI.WebControls;
 7 using System.Drawing;
 8 
 9 namespace Ajax.验证码
10 {
11     public partial class Yanma : System.Web.UI.Page
12     {
13         private int CodeNum = 4;
14         private string codeNum = "";
15         protected void Page_Load(object sender, EventArgs e)
16         {
17             VeriflcationCode();
18             HuaCode(codeNum);
19         }
20 
21         private void VeriflcationCode()
22         {
23             //生成验证码
24             string AllChar = "1,2,3,4,5,6,7,8,9,0,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";
25             string[] StrChar = AllChar.Split(',');
26             Random rd = new Random();
27             string Codes = "";
28             for (int i = 0; i < CodeNum; i++)
29             {
30                 Codes += StrChar[rd.Next(0, 35)];
31             }
32             codeNum = Codes;
33             Session["VerCode"] = Codes; 
34         }
35 
36         private void HuaCode(string Codes)
37         {
38             int iwidth = (int)(Codes.Length * 17);//定义画布的宽
39             System.Drawing.Bitmap images = new System.Drawing.Bitmap(iwidth, 25);//声明一个画布类，初始化图片的宽和高
40 
41             Graphics g = Graphics.FromImage(images);
42             Font f = new Font("Arial", 14);//定义文字类型
43             Brush b = new System.Drawing.SolidBrush(Color.Black);//文字颜色 黑色
44             Brush r = new System.Drawing.SolidBrush(Color.FromArgb(166, 8, 8));//文字颜色 
45             g.Clear(System.Drawing.ColorTranslator.FromHtml("#99C1CB"));//背景色
46 
47             char[] ch = Codes.ToCharArray();
48             for (int i = 0; i < ch.Length; i++)
49             {
50                 if (ch[i] >= '0' && ch[i] <= '9')
51                 {
52                     //数字用红色显示 
53                     g.DrawString(ch[i].ToString(), f, r, 3 + (i * 14), 3);//将文字画出 文字、字体类型、字体颜色、字体间距、字体于顶部间距
54                 }
55                 else
56                 {   //字母用黑色显示
57                     g.DrawString(ch[i].ToString(), f, b, 3 + (i * 14), 3);
58                 }
59             }
60 
61             //for循环用来生成一些随机的水平线
62             Pen blackPen = new Pen(Color.Black, 0);
63             Random rand = new Random();
64             for (int i = 0; i < 5; i++)
65             {
66                 int y = rand.Next(images.Height);
67                 g.DrawLine(blackPen, 0, y, images.Width, y);
68             }
69 
70 
71             System.IO.MemoryStream ms = new System.IO.MemoryStream();
72             images.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
73             //history back 不重复 
74             Response.Cache.SetNoStore();//这一句         
75             Response.ClearContent();
76             Response.ContentType = "image/Jpeg";
77             Response.BinaryWrite(ms.ToArray());
78             g.Dispose();
79             images.Dispose();
80         }

效果为：