生成验证码图片(.net2005/c#)-优快云博客

本文链接：https://blog.youkuaiyun.com/yeelong/article/details/2243342

本文介绍了一种生成验证码图片的方法，包括生成随机数及基于这些随机数创建带有背景噪音线和前景噪音点的验证码图片。文章详细展示了使用C#进行编程的过程。

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文章不是我写的，在我们永远在一起论坛上摘抄下来的，感谢“坛主”给我这个做开山的机会！如有冒犯，敬请原谅，学习为主！

using System;
using System.Drawing;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text.RegularExpressions;
using System.IO;
using System.Drawing.Imaging;
using System.Text;
using System.Web.Security;

/// <summary>
        /// 生成随机数
        /// </summary>
        /// <returns></returns>
        private string GenerateCheckCode()
        {
            #region
            int number;
            char code;
            string checkCode = String.Empty;

System.Random random = new Random();

            for (int i = 0; i < 5; i++)
            {
                number = random.Next();

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

checkCode += code.ToString();
}

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

            return checkCode;
            #endregion
        }

        /// <summary>
        /// 生成验证码图片
        /// </summary>
        public void CreateCheckCodeImage()
        {
            #region
            string checkCode = GenerateCheckCode();
            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 - 1, image.Height - 1);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.ContentType = "image/Gif";
                HttpContext.Current.Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
            #endregion
        }