asp.net 编写验证码

首先准备一个类来实现对验证码的绘制功能。

createcode.cs

  1 using System;

  2 using System.Collections.Generic;

  3 using System.Linq;

  4 using System.Web;

  5 using System.Drawing;

  6 using System.IO;

  7 using System.Configuration;

  8 

  9 

 10 namespace LoginProject

 11 {

 12     public class createcode

 13     {

 14         static string yanzheng = "";

 15         int length = 4;

 16         int fontsize = 25;

 17         string[] fontfamily = { "Arial Narrow", "Baskerville Old Face", "Algerian" };

 18         Color[] colors = { Color.Red, Color.Pink, Color.Plum, Color.Purple, Color.PaleTurquoise, Color.Orchid };//颜色

 19         string CodeValue = "1,2,3,4,5,6,7,8,9,0,a,b,c,d,e,f,g,h,l,i,j,k,m,n,o,p,q,r,s,t,w,q,y,u,x,z"; //值

 20         int imgwidth = 100; //图片宽

 21         int imgheight = 30; //图片高

 22         public static string YanZheng

 23         {

 24             get { return yanzheng; }

 25         }

 26         public int GetLength

 27         {

 28             get { return length; }

 29             set { length = value; }

 30         }

 31         public int FontSize

 32         {

 33             get { return fontsize; }

 34             set { fontsize = value; }

 35         }

 36         public string[] FontFamily

 37         {

 38             get { return fontfamily; }

 39             set { fontfamily = value; }

 40         }

 41         public Color[] GetColor

 42         {

 43             get { return colors; }

 44             set { colors = value; }

 45         }

 46         public string codevalue

 47         {

 48             get { return CodeValue; }

 49             set { CodeValue = value; }

 50         }

 51         public int ImaHeight

 52         {

 53             get { return imgheight; }

 54         }

 55         public int ImaWidth

 56         { get { return imgwidth; } }

 57         //产生随机字母

 58         public string createvalue()

 59         {

 60             string val = "";

 61             string[] arr = codevalue.Split(',');

 62             Random rand = new Random();

 63             for (int i = 0; i < GetLength; i++)

 64             {

 65                 int strindex = rand.Next(0, arr.Length - 1);

 66                 val = val + arr[strindex];

 67             }

 68             yanzheng = val;

 69             return val;

 70         }

 71         //绘制背景图像

 72         public void DrawImage(Bitmap map)

 73         {

 74             Random rand = new Random();

 75             for (int i = 0; i < map.Width; i++)

 76             {

 77                 for (int j = 0; j < map.Height; j++)

 78                 {

 79                     if (rand.Next(60, 90) < 80)

 80                     {

 81                         map.SetPixel(i, j, Color.Beige);

 82                     }

 83                 }

 84             }

 85         }

 86         //绘制验证码

 87         public void DrawValue(string code, Bitmap bmap)

 88         {

 89             Random rand = new Random();

 90             Graphics g = Graphics.FromImage(bmap);//获取背景图片(获取绘制器对象)

 91 

 92             System.Drawing.StringFormat sF = new StringFormat();

 93             sF.Alignment = StringAlignment.Center;

 94             for (int i = 0; i < code.Length; i++)

 95             {

 96                 System.Drawing.PointF point = new PointF(i * FontSize, 2);

 97                 string cellcode = code[i].ToString();

 98                 Font F = new Font(FontFamily[rand.Next(0, 2)], FontSize, FontStyle.Italic);

 99                 g.DrawString(cellcode, F, Brushes.BlueViolet, point, sF);

100             }

101         }

102         //输出

103         public void Output(string code, HttpContext type)

104         {

105            // System.IO.MemoryStream ms = new MemoryStream();

106             type.Response.ContentType = "image/jpeg";

107             Bitmap bit = new Bitmap(ImaWidth,ImaHeight);

108             this.DrawImage(bit);

109             this.DrawValue(code, bit);

110             bit.Save(type.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);

111             //ms.Close();

112             //ms = null;

113             bit.Dispose();

114             bit = null;

115         }

116     }

117 }

View Code

然后准备一个页面来接收绘制出的验证码图片，如下

yanzhengma.aspx

 1 <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="yanzhengma.aspx.cs" Inherits="LoginProject.yanzhengma" %>

 2 

 3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

 4 

 5 <html xmlns="http://www.w3.org/1999/xhtml">

 6 <head runat="server">

 7     <title></title>

 8 </head>

 9 <body>

10     <form id="form1" runat="server">

11     <div>

12     <asp:Image  ID="imag" Width="100px" Height="50px" runat="server" ImageUrl="~/yanzhengma.aspx"/>

13     </div>

14     </form>

15 </body>

16 </html>

yanzhengma.aspx.cs

 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 

 8 namespace LoginProject

 9 {

10     public partial class yanzhengma : System.Web.UI.Page

11     {

12         protected void Page_Load(object sender, EventArgs e)

13         {

14             createcode code = new createcode();

15             string strcode = code.createvalue();

16             code.Output(strcode, this.Context);

17         }

18     }

19 }

如果想实现“看不清换一张”的功能则需要在另外使用一个接收页面。这个页面就是你的登陆页面代码如下

 1 <script type="text/javascript">

 2         function change() {

 3             var img = document.getElementById("Image1");

 4             img.src = img.src + '?';

 5         }

 6     </script>

 7 

 8 <td class="style1">验证码</td>

 9                 <td>

10                  <asp:TextBox ID="yanzheng" runat="server" Width="150px" Height="25px"></asp:TextBox><label><img  id="Image1" style=" Width:150px; Height:30px;" src="yanzhengma.aspx" alt="看不清换一张" onclick="change()"/></label>

11                 </td>

当然还有其他的页面排版呀什么的，我就不一一写出来，就把最主要的部分写出来。

最后的效果，图片比较丑，主要还是个人的美工不好哇！

希望能帮到你哟..........