.Net随机中文验证码

1.前台.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ValidateCode.aspx.cs" Inherits="ValidateCode" %>

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

</head>

<body>

<div>

</div>

</form>

</body>

</html>

2.后台.cs

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Drawing;

using System.Text;

public partial class ValidateCode : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

//调用函数产生4个随机中文汉字编码

string randomcode = CreateRegionCode(4);

Session["ValidateCode"] = randomcode;

//ViewState["ValidateCode"] = randomcode;

this.CreateImage(randomcode);

}

/// <summary>

/// 中文

/// </summary>

/// <param name="strlength"></param>

/// <returns></returns>

public string CreateRegionCode(int strlength)

{

//定义一个字符串数组储存汉字编码的组成元素

string[] rBase = new String[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

Random rnd = new Random();

//定义一个object数组用来

object[] bytes = new object[strlength];

/**/

/*每循环一次产生一个含两个元素的十六进制字节数组，并将其放入bject数组中

每个汉字有四个区位码组成

区位码第1位和区位码第2位作为字节数组第一个元素

区位码第3位和区位码第4位作为字节数组第二个元素

for (int i = 0; i < strlength; i++)

{

//区位码第1位

int r1 = rnd.Next(11, 14);

string str_r1 = rBase[r1].Trim();

//区位码第2位

rnd = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i);//更换随机数发生器的种子避免产生重复值

int r2;

if (r1 == 13)

r2 = rnd.Next(0, 7);

else

r2 = rnd.Next(0, 16);

string str_r2 = rBase[r2].Trim();

//区位码第3位

rnd = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);

int r3 = rnd.Next(10, 16);

string str_r3 = rBase[r3].Trim();

//区位码第4位

rnd = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i);

int r4;

if (r3 == 10)

r4 = rnd.Next(1, 16);

else if (r3 == 15)

r4 = rnd.Next(0, 15);

else

r4 = rnd.Next(0, 16);

string str_r4 = rBase[r4].Trim();

//定义两个字节变量存储产生的随机汉字区位码

byte byte1 = Convert.ToByte(str_r1 + str_r2, 16);

byte byte2 = Convert.ToByte(str_r3 + str_r4, 16);

//将两个字节变量存储在字节数组中

byte[] str_r = new byte[] { byte1, byte2 };

//将产生的一个汉字的字节数组放入object数组中

bytes.SetValue(str_r, i);

}

//获取GB2312编码页（表）

Encoding gb = Encoding.GetEncoding("gb2312");

//根据汉字编码的字节数组解码出中文汉字

string strResult = "";

for (int i = 0; i < strlength; i++)

{

strResult += gb.GetString((byte[])Convert.ChangeType(bytes[i], typeof(byte[])));

}

return strResult;

}

/// <summary>

/// 创建随机码图片

/// </summary>

/// <param name="randomcode">随机码</param>

private void CreateImage(string randomcode)

{

int randAngle = 30; //随机转动角度

int mapwidth = (int)(randomcode.Length * 28);

Bitmap map = new Bitmap(mapwidth, 28);//创建图片背景

Graphics graph = Graphics.FromImage(map);

graph.Clear(Color.AliceBlue);//清除画面，填充背景

graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框

//graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式

Random rand = new Random();

//背景噪点生成

Pen blackPen = new Pen(Color.LightGray, 0);

for (int i = 0; i < 50; i++)

{

int x = rand.Next(0, map.Width);

int y = rand.Next(0, map.Height);

graph.DrawRectangle(blackPen, x, y, 1, 1);

}

//验证码旋转，防止机器识别

char[] chars = randomcode.ToCharArray();//拆散字符串成单字符数组

//文字距中

StringFormat format = new StringFormat(StringFormatFlags.NoClip);

format.Alignment = StringAlignment.Center;

format.LineAlignment = StringAlignment.Center;

//定义颜色

Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };

//定义字体

string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

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

{

int cindex = rand.Next(7);

int findex = rand.Next(5);

Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)

Brush b = new System.Drawing.SolidBrush(c[cindex]);

Point dot = new Point(22, 16);

//graph.DrawString(dot.X.ToString(),fontstyle,new SolidBrush(Color.Black),10,150);//测试X坐标显示间距的

float angle = rand.Next(-randAngle, randAngle);//转动的度数

graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置

graph.RotateTransform(angle);

graph.DrawString(chars[i].ToString(), f, b, 1, 1, format);

//graph.DrawString(chars[i].ToString(),fontstyle,new SolidBrush(Color.Blue),1,1,format);

graph.RotateTransform(-angle);//转回去

graph.TranslateTransform(2, -dot.Y);//移动光标到指定位置

}

//graph.DrawString(randomcode,fontstyle,new SolidBrush(Color.Blue),2,2); //标准随机码

//生成图片

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

map.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);

Response.ClearContent();

Response.ContentType = "image/gif";

Response.BinaryWrite(ms.ToArray());

graph.Dispose();

map.Dispose();

}

3.调用页面.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default3.aspx.cs" Inherits="Default3" %>

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

function ValidateCode(imgId)

{

var img = document.getElementById(imgId);

img.src = "ValidateCode.aspx?" + Math.random();

}

</script>