validcode.aspx.cs

Asp.net简单实现一个复杂的验证码

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.Imaging;
using System.Drawing.Drawing2D;
using System.Drawing;

//该源码下载自www.51aspx.com(５１ａｓｐｘ．ｃｏｍ)
namespace ComplexValide
{
    public partial class ValidCode : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            Random rd = new Random(); //创建随机数对象       

        //以下4行,产生由6个字母和数字组成的一个字符串
        string str = "ABCDEFGHIJKLMNOPQRSTURWXYZ0123456789我的复杂验证源码";
        string my51aspx = "";
        for (int i = 0; i < 6; i++)
        {
            my51aspx = my51aspx + str.Substring(rd.Next(42), 1);
        }
        //验证码值存放到Session中用来比较
        Session["Valid"] = my51aspx;

        //以下三句,通过随机找一个现有图象产生一个画布Bitmap
        string bgFilePath = Server.MapPath(".\\images\\bg" + new Random().Next(5) + ".jpg");//随机找个图象
        System.Drawing.Image imgObj = System.Drawing.Image.FromFile(bgFilePath);
        Bitmap newBitmap = new Bitmap(imgObj, 290, 80);//建立位图对象

        Graphics g = Graphics.FromImage(newBitmap);//根据上面创建的位图对象创建绘图面
        SolidBrush brush = new SolidBrush(Color.Black);//设置画笔颜色

        //定义一个含10种字体的数组
        String[] fontFamily ={ "Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler", "Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow" };

        //通过循环,绘制每个字符,
        for (int a = 0; a < my51aspx.Length; a++)
        {
            Font textFont = new Font(fontFamily[rd.Next(9)], 30, FontStyle.Bold);//字体随机,字号大小30,加粗 
            //每次循环绘制一个字符,设置字体格式,画笔颜色,字符相对画布的X坐标,字符相对画布的Y坐标
            g.DrawString(my51aspx.Substring(a, 1), textFont, brush, 40 + a * 36, 20);
        }

        //保存画的图片到输出流中
        newBitmap.Save(Response.OutputStream, ImageFormat.Gif);

    }

        }
    }