C#生成验证码图片的方法

/// <summary>    /// 生成验证码图片    /// </summary>    /// <returns></returns>    public byte[] GetVerifyCode()    {      int codeW = 80;      int codeH = 40;      int fontSize = 18;      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" };      //验证码的字符集，去掉了一些容易混淆的字符       char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };      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)];      }      //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 < 1; 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, (float)0);      }      //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);        return ms.ToArray();      }      catch (Exception)      {        return null;      }      finally      {        g.Dispose();        bmp.Dispose();      }    }