极点博客 网络软件、编程技术博客

(C#)生成图形随机验证码(winform)

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.CreateCheckCodeImage(GenerateCheckCode());
    }

    //产生随机数的函数
    private string GenerateCheckCode()
    {
        int number;
        char code;
        //空字符串且为只读属性
        string checkCode = String.Empty;
        //新建一个随机数产生器
        System.Random random = new Random();
        for (int i = 0; i < 5; i++)
        {   //随机产生一个整数
            number = random.Next();
            //如果随机数是偶数 取余
            if (number % 2 == 0)
                code = (char)('0' + (char)(number % 10));
            else
                //如果随机数是奇数 选择从[A-Z]
                code = (char)('A' + (char)(number % 26));
            //5个字符的组合
            checkCode += code.ToString();
        }
        //将字符串checkCode写入Cookies并且返回字符串checkCode
        Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
        return checkCode;
    }
    //建立一个随机图形
    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;
        //建立一个位图文件 确立长宽
        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);
            }
            //把产生的随机数以字体的形式写入画面
            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);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }

}

标签: 编程基础

作者:xtpyeihc 分类:先前文章 浏览:193 评论:0
留言列表
发表评论
来宾的头像