web页面验证码代码

private void CreateCheckCodeImage(string[] checkCode)

{

if (checkCode == null || checkCode.Length <= 0)

return;

System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 32.5)), 30);

System.Drawing.Graphics g = Graphics.FromImage(image);

try

{

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 < 20; 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);

}

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

for (int k = 0; k <= checkCode.Length - 1; k++)

{

int cindex = random.Next(7);

int findex = random.Next(5);

Font drawFont = new Font(f[findex], 15, (System.Drawing.FontStyle.Bold));

SolidBrush drawBrush = new SolidBrush(c[cindex]);

float x = 5.0F;

float y = 0.0F;

float width = 20.0F;

float height = 25.0F;

int sjx = random.Next(10);

int sjy = random.Next(image.Height - (int)height);

RectangleF drawRect = new RectangleF(x + sjx + (k * 25), y + sjy, width, height);

StringFormat drawFormat = new StringFormat();

drawFormat.Alignment = StringAlignment.Center;

g.DrawString(checkCode[k], drawFont, drawBrush, drawRect, drawFormat);

}

//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()));

}

//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();

}

}