生成验证码

来源：互联网发布：小米监控软件编辑：程序博客网时间：2024/06/10 09:46

页面

<HTML>
<HEAD>
  <title>GenerateCheckCode</title>
  <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
  <meta name="CODE_LANGUAGE" Content="C#">
  <meta name="vs_defaultClientScript" content="JavaScript">
  <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
  <form id="Form1" method="post" runat="server">
   <FONT face="宋体">
    <asp:ImageButton id="ImageButton1" style="Z-INDEX: 101; LEFT: 40px; POSITION: absolute; TOP: 32px"
     runat="server" ImageUrl="~/GenerateCheckCode.aspx"></asp:ImageButton></FONT>
  </form>
</body>
</HTML>

private void Page_Load(object sender, System.EventArgs e)
  {
   // 在此处放置用户代码以初始化页面
   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", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };
   //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', '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)];
   }
   Bitmap bmp = new Bitmap(100, 40);
   Graphics g = Graphics.FromImage(bmp);
   g.Clear(Color.White);
   //画噪线
   for (int i = 0; i < 10; i++)
   {
    int x1 = rnd.Next(100);
    int y1 = rnd.Next(40);
    int x2 = rnd.Next(100);
    int y2 = rnd.Next(40);
    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, 18);
    Color clr = color[rnd.Next(color.Length)];
    g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 20 + 8, (float)8);
   }
   //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
   Response.Buffer = true;
   Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
   Response.Expires = 0;
   Response.CacheControl = "no-cache";
   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);
    Response.ClearContent();
    Response.ContentType = "image/Png";
    Response.BinaryWrite(ms.ToArray());
   }
   finally
   {
    //显式释放资源
    bmp.Dispose();
    g.Dispose();
   }
  }