asp.net汉语验证码

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 Admin_ValidCode : System.Web.UI.Page 
{ 
protected void Page_Load(object sender, EventArgs e) 
{ 
this.CreateCheckCodeImage(GenerateCheckCode()); 
} 
private string GenerateCheckCode() 
{ 
int number; 
//char code; 
string checkCode = String.Empty; 
System.Random random = new Random(); 
Encoding gb = Encoding.GetEncoding("gb2312"); 
//调用函数产生4个随机中文汉字编码 
object[] bytes = CreateRegionCode(6); 
//根据汉字编码的字节数组解码出中文汉字 
string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[]))); 
string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[]))); 
string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[]))); 
string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[]))); 
//输出的控制台 
checkCode = str1 + str2 + str3 + str4; 
//for (int i = 0; i < 5; i++) 
//{ 
// number = random.Next(); 
// if (number % 2 == 0) 
// code = (char)('0' + (char)(number % 10)); 
// else 
// code = (char)('A' + (char)(number % 26)); 
// checkCode += code.ToString(); 
//} 
Response.Cookies.Add(new HttpCookie("ValidCode",LjfLib.Encrypt.AES.EncryptAes(checkCode))); 
//Session["ValidCode"] = checkCode;

return checkCode; 
} 
#region 产生波形滤镜效果 
private static object[] 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); 
} 
return bytes; 
} 
private const double PI = 3.1415926535897932384626433832795; 
private const double PI2 = 6.283185307179586476925286766559; 
private System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase) 
{ 
System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); 
// 将位图背景填充为白色 
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp); 
graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height); 
graph.Dispose(); 
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width; 
for (int i = 0; i < destBmp.Width; i++) 
{ 
for (int j = 0; j < destBmp.Height; j++) 
{ 
double dx = 0; 
dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen; 
dx += dPhase; 
double dy = Math.Sin(dx); 
// 取得当前点的颜色 
int nOldX = 0, nOldY = 0; 
nOldX = bXDir ? i + (int)(dy * dMultValue) : i; 
nOldY = bXDir ? j : j + (int)(dy * dMultValue); 
System.Drawing.Color color = srcBmp.GetPixel(i, j); 
if (nOldX >= 0 && nOldX < destBmp.Width 
&& nOldY >= 0 && nOldY < destBmp.Height) 
{ 
destBmp.SetPixel(nOldX, nOldY, color); 
} 
} 
} 
return destBmp; 
} 
#endregion 
private void CreateCheckCodeImage(string checkCode) 
{ 
if (checkCode == null 　　 checkCode.Trim() == String.Empty) 
return; 
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 27.0)), 25); 
Graphics g = Graphics.FromImage(image); 
try 
{ 
//生成随机生成器 
Random random = new Random(); 
//清空图片背景色 
g.Clear(Color.White); 
//画图片的背景噪音线 
for (int i = 0; i < 12; i++) 
{ 
int x1 = random.Next(image.Width); 
int x2 = random.Next(image.Width); 
int y1 = random.Next(image.Height); 
int y2 = random.Next(image.Height); 
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); 
} 
//Font font = new System.Drawing.Font("Arial", 16, (System.Drawing.FontStyle.Bold 　 System.Drawing.FontStyle.Italic)); 
Font font = new System.Drawing.Font("楷体_GB2312", 16, (System.Drawing.FontStyle.Bold)); 
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); 
g.DrawString(checkCode, font, brush, 2, 2); 
//画图片的前景噪音点 
for (int i = 0; i < 100; i++) 
{ 
int x = random.Next(image.Width); 
int y = random.Next(image.Height); 
image.SetPixel(x, y, Color.FromArgb(random.Next())); 
} 
//image = TwistImage(image, true, 3, 1); 
//画图片的波形滤镜效果 
//画图片的边框线 
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); 
System.IO.MemoryStream ms = new System.IO.MemoryStream(); 
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); 
Response.ClearContent(); 
Response.ContentType = "image/Gif"; 
Response.BinaryWrite(ms.ToArray()); 
} 
finally 
{ 
g.Dispose(); 
image.Dispose(); 
} 
} 
}