c#写的验证码随即产生六个汉字

c#写的验证码随即产生六个汉字

默认分类 2008-07-16 11:05:14 阅读4 评论0   字号：大中小 订阅

using System;
using System.Text;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
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;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //获取GB2312编码页（表）
        Encoding gb = Encoding.GetEncoding("gb2312");

        //调用函数产生6个随机中文汉字编码
        object[] bytes = CreateRegionCode(6);

        //根据汉字编码的字节数组解码出中文汉字
        string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[])));
        string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[])));
        string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[])));
        string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[])));
        string str5 = gb.GetString((byte[])Convert.ChangeType(bytes[4], typeof(byte[])));
        string str6 = gb.GetString((byte[])Convert.ChangeType(bytes[5], typeof(byte[])));

        //输出的控制台
        this.CreateImage(str1 + str2 + str3 + str4 + str5 + str6);
    }

    /*
    此函数在汉字编码范围内随机创建含两个元素的十六进制字节数组，每个字节数组代表一个汉字，并将
    四个字节数组存储在object数组中。
    参数：strlength，代表需要产生的汉字个数
    */

    public static object[] CreateRegionCode(int strlength)
    {
        //定义一个字符串数组储存汉字编码的组成元素
        string[] rBase = new String[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

        Random rnd = new Random();

        //定义一个object数组用来
        object[] bytes = new object[strlength];

     
        /*每循环一次产生一个含两个元素的十六进制字节数组，并将其放入bject数组中
         每个汉字有四个区位码组成
         区位码第1位和区位码第2位作为字节数组第一个元素
         区位码第3位和区位码第4位作为字节数组第二个元素
        */
        for (int i = 0; i < strlength; i++)
        {
            //区位码第1位
            int r1 = rnd.Next(11, 14);
            string str_r1 = rBase[r1].Trim();

            //区位码第2位
            rnd = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i);//更换随机数发生器的种子避免产生重复值
            int r2;
            if (r1 == 13)
            {
                r2 = rnd.Next(0, 7);
            }
            else
            {
                r2 = rnd.Next(0, 16);
            }
            string str_r2 = rBase[r2].Trim();

            //区位码第3位
            rnd = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);
            int r3 = rnd.Next(10, 16);
            string str_r3 = rBase[r3].Trim();

            //区位码第4位
            rnd = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i);
            int r4;
            if (r3 == 10)
            {
                r4 = rnd.Next(1, 16);
            }
            else if (r3 == 15)
            {
                r4 = rnd.Next(0, 15);
            }
            else
            {
                r4 = rnd.Next(0, 16);
            }
            string str_r4 = rBase[r4].Trim();

            //定义两个字节变量存储产生的随机汉字区位码
            byte byte1 = Convert.ToByte(str_r1 + str_r2, 16);
            byte byte2 = Convert.ToByte(str_r3 + str_r4, 16);
            //将两个字节变量存储在字节数组中
            byte[] str_r = new byte[] { byte1, byte2 };

            //将产生的一个汉字的字节数组放入object数组中
            bytes.SetValue(str_r, i);
        }
        return bytes;
    }

    private void CreateImage(string checkCode)
    {
        Random random = new Random();
        int iwidth = (int)(checkCode.Length * 21);
        Bitmap image = new Bitmap(iwidth, 21);
        Graphics g = Graphics.FromImage(image);
        Font f = new Font("Arial", 12, FontStyle.Bold);
        SolidBrush b = new System.Drawing.SolidBrush(Color.DarkOrange);
        //g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue), 0, 0, image.Width, image.Height);
        g.Clear(Color.White);
        g.DrawString(checkCode, f, b, 1, 1);

        //画图片的前景的直线
        Color a = Color.FromArgb(random.Next());
        Pen blackPen = new Pen(a, 0);
        Random rand = new Random();
        for (int i = 0; i < 4; i++)
        {
            int y = rand.Next(image.Height);
            g.DrawLine(blackPen, 0, y, image.Width, y);
        }

        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        Response.ClearContent();
        Response.ContentType = "image/Jpeg";
        Response.BinaryWrite(ms.ToArray());
        g.Dispose();
        image.Dispose();
    }
}