C#创建图片验证码

try
{
int iMapWidth = codes.Length * 21;
Bitmap map = new Bitmap(iMapWidth, 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 抗锯齿

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 = codes.ToCharArray();//拆散字符串成单字符数组

//文字距中
StringFormat format = new StringFormat(StringFormatFlags.NoClip);//允许显示标志符号的伸出部分和延伸到边框外的未换行文本。在默认情况下，延伸到边框外侧的所有文本和标志符号部分都被剪裁。
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]);

graph.DrawString(chars[i].ToString(), f, b, i*16+8, 15, format);

}

this.pictureBox1.Image = map;

}
catch (ArgumentException ex)
{
MessageBox.Show("创建图片验证码错误，错误原因："+ex.Message.ToString());
}