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  • .net生成图片验证码

    /************************************************************************/
    /* 类名:无
    * 功能:生成验证码图片
    * 完成时间:2009-8-11
    * 版本号:1.0
    * 修改时间:
    * 作者:eping
    * E-Mail:eping@live.com
    /************************************************************************/
    using System;
    using System.Data;
    using System.Configuration;
    using System.Web;
    using System.Web.Security;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.UI.WebControls.WebParts;
    using System.Web.UI.HtmlControls;

    using System.Drawing;  //添加引用

    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            //调用自定义方法绘制验证码
            CreateCheckCodeImage(GenerateCheckCode());
        }

        private string GenerateCheckCode()
        {
            //创建整型型变量
            int number;
            //创建字符型变量
            char code;
            //创建字符串变量并初始化为空
            string checkCode = String.Empty;
            //创建Random对象
            Random random = new Random();
            //使用For循环生成4个数字
            for (int i = 0; i < 4; i++)
            {
                //生成一个随机数
                number = random.Next();
                //将数字转换成为字符型
               code = (char)('0' + (char)(number % 10));        

                checkCode += code.ToString();
            }
            //将生成的随机数添加到Cookies中
            Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
            //返回字符串
            return checkCode;
        }

        private void CreateCheckCodeImage(string checkCode)
        {
            //判断字符串不等于空和null
            if (checkCode == null || checkCode.Trim() == String.Empty)
                return;
           //创建一个位图对象
            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
            //创建Graphics对象
            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 < 2; 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.Black), x1, y1, x2, y2);
                }

                Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
                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);

                //将图片输出到页面上
                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();
            }
        }
    }

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  • 原文地址:https://www.cnblogs.com/zxk3113/p/3880550.html
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