C#繪製漢字驗證碼 源碼

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.Text;  //添加引用
using System.Drawing;  //添加引用

public partialclass
_Default : System.Web.UI.Page
{
    protected voidPage_Load(object
sender, EventArgs e)
    {
        GraphicsImage(4);  //調用方法產生四位漢字驗證碼
    }

    private object[] CreateString(intstrlength)
    {
        //定義一個數組儲存漢字編碼的組成元素
        string[] str = new string[16] { "0", "1", "2", "3", "4",
"5", "6", "7", "8","9",
"a", "b", "c","d",
"e", "f" };

        Random
ran = new Random();  //定義一個隨機數對象
        object[] bytes =
new object[strlength];
        for (int
i = 0; i < strlength; i++)
        {
            //擷取區位碼第一位
            int ran1 = ran.Next(11, 14);
            string str1 = str[ran1].Trim();

            //擷取區位碼第二位並防止資料重複
            ran = new Random(ran1 *
unchecked((int)DateTime.Now.Ticks) + i);
            int ran2;
            if (ran1 == 13)
            {
                ran2 = ran.Next(0, 7);
            }
            else
            {
                ran2 = ran.Next(0, 16);
            }
            string str2 = str[ran2].Trim();

            //擷取區位碼第三位
            ran = new Random(ran2 *unchecked((int)DateTime.Now.Ticks) + i);
            int ran3 = ran.Next(10, 16);
            string str3 = str[ran3].Trim();

            //擷取區位碼第四位
            ran = new Random(ran3 *unchecked((int)DateTime.Now.Ticks) + i);
            int ran4;
            if (ran3 == 10)
            {
                ran4 = ran.Next(1, 16);
            }
            else if(ran3 == 15)
            {
                ran4 = ran.Next(0, 15);
            }
            else
            {
                ran4 = ran.Next(0, 16);
            }
            string str4 = str[ran4].Trim();

            //定義位元組變數儲存產生的隨機漢字區位碼
            byte byte1 =
Convert.ToByte(str1 + str2, 16);
            byte byte2 =
Convert.ToByte(str3 + str4, 16);

            byte[] stradd =new
byte[] { byte1,byte2};
            //將產生的漢字位元組放入數組
            bytes.SetValue(stradd, i);
        }
        return bytes;
    }

    private string GetString(int length)
    {
        Encoding gb =
Encoding.GetEncoding("gb2312");
        object[] bytes = CreateString(length);

        //根據漢字位元組解碼出中文漢字
        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
str = str1 + str2 + str3 + str4;
        Response.Cookies.Add(new HttpCookie("CheckCode",str));
        return str;
    }

    private voidGraphicsImage(int
length)
    {
        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((GetString(length).Length * 22.5)),
22);
        Graphics g =
Graphics.FromImage(image);  //建立畫布

        try
        {
            //產生隨機產生器
            Random random =
new Random();

            //清空圖片背景色
            g.Clear(Color.White);

            //畫圖片的背景雜音線
            for (inti = 0; i < 1; 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(newPen(Color.Black), x1, y1, x2, y2);
            }

            Font
font = new System.Drawing.Font("Couriew New",12, System.Drawing.FontStyle.Bold );
            System.Drawing.Drawing2D.LinearGradientBrushbrush =
new System.Drawing.Drawing2D.LinearGradientBrush
                (new Rectangle(0, 0, image.Width, image.Height),Color.Blue,
Color.DarkRed, 1.2f,true);
            g.DrawString(GetString(length), font, brush, 2, 2);

            //畫圖片的前景噪音點
            for (inti = 0; i < 50; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);

                image.SetPixel(x, y,
Color.FromArgb(random.Next()));
            }

            //畫圖片的邊框線
            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());
        }
        catch (Exceptionms)
        {
            Response.Write(ms.Message);
        }

    }
}