.net code：
public void ValidateCode()
{
// 在此处放置用户代码以初始化页面
string vnum;
vnum = GetByRndNum(6);
Response.ClearContent(); //需要输出图象信息 要修改HTTP头
Response.ContentType = "image/jpeg";
CreateValidateCode(vnum);
}
private void CreateValidateCode(string vnum)
{
Bitmap Img = null;
Graphics g = null;
Random random = new Random();
int gheight = vnum.Length * 15;
Img = new Bitmap(gheight, 24);
g = Graphics.FromImage(Img);
Font f = new Font("宋体", 14, FontStyle.Bold);
//Font f = new Font("宋体", 9, FontStyle.Bold);
g.Clear(Color.White);//设定背景色
Pen blackPen = new Pen(ColorTranslator.FromHtml("#BCBCBC"), 3);
for (int i = 0; i < 128; i++)// 随机产生干扰线，使图象中的认证码不易被其它程序探测到
{
int x = random.Next(gheight);
int y = random.Next(20);
int xl = random.Next(6);
int yl = random.Next(2);
g.DrawLine(blackPen, x, y, x + xl, y + yl);
}
SolidBrush s = new SolidBrush(ColorTranslator.FromHtml("#411464"));
g.DrawString(vnum, f, s, 3, 3);
//画边框
blackPen.Width = 1;
g.DrawRectangle(blackPen, 0, 0, Img.Width - 1, Img.Height - 1);
Img.Save(Response.OutputStream, ImageFormat.Jpeg);
s.Dispose();
f.Dispose();
blackPen.Dispose();
g.Dispose();
Img.Dispose();
//Response.End();
}
//-----------------给定范围获得随机颜色------------
Color GetByRandColor(int fc, int bc)
{
Random random = new Random();
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
//if(ac>255) ac=255;
int r = fc + random.Next(bc - fc);
int g = fc + random.Next(bc - fc);
int b = fc + random.Next(bc - bc);
Color rs = Color.FromArgb(r, g, b);
return rs;
}
public string GetByRndNum(int VcodeNum)
{
string VNum = "";
Random rand = new Random();
for (int i = 0; i < VcodeNum; i++)
{
VNum += VcArray[rand.Next(0, 9)];
}
Session["Code"] = VNum;
return VNum;
}
private static readonly string[] VcArray = new string[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };