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验证码图片生成代码

news 来源：原创 2024/5/5 15:21:19

验证码图片生成代码

     using System.Drawing;

     public partial class Pub_validcode : System.Web.UI.Page
    {
     protected void Page_Load( object sender, EventArgs e)
    {
         this .CreateCheckCodeImage(GenerateCheckCode());
    }

     // 生成随机数
     private string GenerateCheckCode()
    {
         int number;
         char code;
         string checkCode = String.Empty;

        System.Random random = new Random();

         for ( int i = 0 ; i < 4 ; i ++ )
        {
            number = random.Next();

             if (number % 2 == 0 )
                code = ( char )( ' 0 ' + ( char )(number % 10 ));
             else
                code = ( char )( ' 0 ' + ( char )(number % 10 ));
             // code = (char)('a' + (char)(number % 26));

            checkCode += code.ToString();
        }

        Response.Cookies.Add( new HttpCookie( " CheckCode " , checkCode));

         // 将生成的随机数保存到session中

        Session[ " Num " ] = checkCode.ToString().ToLower();

         return checkCode;
    }

     private void CreateCheckCodeImage( string checkCode)
    {
         if (checkCode == null || checkCode.Trim() == String.Empty)
             return ;

        System.Drawing.Bitmap image = new System.Drawing.Bitmap(( int )Math.Ceiling((checkCode.Length * 12.5 )), 22 );
        Graphics g = Graphics.FromImage(image);

         try
        {
             // 生成随机生成器
            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 < 25 ; 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);
            }

            Font font = new System.Drawing.Font( " Arial " , 12 , (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush( new Rectangle( 0 , 0 , image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f , true );
            g.DrawString(checkCode, font, brush, 2 , 2 );

             // 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 - 2 , 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();
        }
    }
}

前台调用代码

function refresh()
{
    $( " imgValid " ).src = " ValidCode.aspx?temp= " + ( new Date().getTime().toString( 36 ));
     return false ;
}
< img id = " imgValid " src = " ValidCode.aspx " onclick = " javascript:refresh(); " alt = ""/ >

转载于:https://www.cnblogs.com/hwx0807/archive/2010/08/09/1795670.html