/// <summary> /// 验证码生成类 /// </summary> public class verify_code : IHttpHandler, IRequiresSessionState {
public void ProcessRequest(HttpContext context) {
int codeW = 80;
int codeH = 22;
int fontSize = 16;
string chkCode = string.Empty;
//颜色列表，用于验证码、噪线、噪点 Color[] color = {
Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue }
;
//字体列表，用于验证码 string[] font = {
"Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" }
;
//验证码的字符集，去掉了一些容易混淆的字符 char[] character = {
'0', '1', '2', '3', '4', '5', '6', '8', '9' }
;
Random rnd = new Random();
//生成验证码字符串 for (int i = 0;
i < 4;
i++) {
chkCode += character[rnd.Next(character.Length)];
}
//写入Session context.Session["sys_verify_code"] = chkCode;
//创建画布 Bitmap bmp = new Bitmap(codeW, codeH);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
//画噪线 for (int i = 0;
i < 4;
i++) {
int x1 = rnd.Next(codeW);
int y1 = rnd.Next(codeH);
int x2 = rnd.Next(codeW);
int y2 = rnd.Next(codeH);
Color clr = color[rnd.Next(color.Length)];
g.DrawLine(new Pen(clr), x1, y1, x2, y2);
}
//画验证码字符串 for (int i = 0;
i < chkCode.Length;
i++) {
string fnt = font[rnd.Next(font.Length)];
Font ft = new Font(fnt, fontSize);
Color clr = color[rnd.Next(color.Length)];
g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18 + 2, (float)0);
}
//画噪点 for (int i = 0;
i < 100;
i++) {
int x = rnd.Next(bmp.Width);
int y = rnd.Next(bmp.Height);
Color clr = color[rnd.Next(color.Length)];
bmp.SetPixel(x, y, clr);
}
//清除该页输出缓存，设置该页无缓存 context.Response.Buffer = true;
context.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
context.Response.Expires = 0;
context.Response.CacheControl = "no-cache";
context.Response.AppendHeader("Pragma", "No-Cache");
//将验证码图片写入内存流，并将其以 "image/Png" 格式输出 MemoryStream ms = new MemoryStream();
try {
bmp.Save(ms, ImageFormat.Png);
context.Response.ClearContent();
context.Response.ContentType = "image/Png";
context.Response.BinaryWrite(ms.ToArray());
}
finally {
//显式释放资源 bmp.Dispose();
g.Dispose();
}
}
public bool IsReusable {
get {
return false;
}
}
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web;
public partial class image : System.Web.UI.Page{
protected void Page_Load(object sender, EventArgs e) {
string tmp = RndNum(4);
HttpCookie a = new HttpCookie("ImageV", tmp);
Response.Cookies.Add(a);
this.ValidateCode(tmp);
}
private void ValidateCode(string VNum) {
Bitmap Img = null;
Graphics g = null;
MemoryStream ms = null;
int gheight = VNum.Length * 12;
Img = new Bitmap(gheight, 25);
g = Graphics.FromImage(Img);
//背景颜色 g.Clear(Color.White);
//文字字体 Font f = new Font("Arial Black", 10);
//文字颜色 SolidBrush s = new SolidBrush(Color.Black);
g.DrawString(VNum, f, s, 3, 3);
ms = new MemoryStream();
Img.Save(ms, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
Img.Dispose();
Response.End();
}
private string RndNum(int VcodeNum) {
string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p" + ",q,r,s,t,u,v,w,x,y,z";
string[] VcArray = Vchar.Split(new Char[] {
',' }
);
string VNum = "";
int temp = -1;
Random rand = new Random();
for (int i = 1;
i < VcodeNum + 1;
i++) {
if (temp != -1) {
rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
}
int t = rand.Next(35);
if (temp != -1 && temp == t) {
return RndNum(VcodeNum);
}
temp = t;
VNum += VcArray[t];
}
return VNum;
}
}