IT工程師數位筆記本

using System;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.IO;
/// <summary>
///ValidateCode 的摘要說明
/// </summary>
namespace ASPNETAJAXWeb.ValidateCode.Page
{
    public class ValidateCode : System.Web.UI.Page
    {
        private const double IMAGELENGTHBASE = 12.5;
        private const int IMAGEHEIGTH = 22;
        private const int IMAGELINENUMBER = 25;
        private const int IMAGEPOINTNUMBER = 100;
        public static string VALIDATECODEKEY = "VALIDATECODEKEY";
        private int length = 4;//驗證碼的數字個數
        private string code = string.Empty;
        public ValidateCode()
        {
            //
            //TODO: 在此處添加構造函數邏輯
            //
        }
        public int Length
        {
            get { return length; }
            set { length = value; }
        }
        public string Code
        {
            get { return Code; }
        }

        /// <summary>
        /// 創建隨機驗證碼
        /// </summary>
        /// <param name="length"></param>
        /// <returns></returns>
        public string CreateCode(int length)
        {
            if (length <= 0)
                return string.Empty;
            Random random = new Random();
            StringBuilder sbCode = new StringBuilder();
            for (int i = 0; i < length; i++)
            {
                sbCode.Append(random.Next(0, 10));
            }
            code = sbCode.ToString();
            Session[VALIDATECODEKEY] = code;
            return code;
        }


        /// <summary>
        /// 創建驗證碼的圖片和驗證碼
        /// </summary>
        /// <param name="code"></param>
        public void CreateValidateImage(string code)
        {
            if (string.IsNullOrEmpty(code) == true)
                return;
            Session[VALIDATECODEKEY] = code;
            Bitmap image = new Bitmap((int)Math.Ceiling((code.Length * IMAGELENGTHBASE)), IMAGEHEIGTH);
            Graphics g = Graphics.FromImage(image);


            ///隨機數生成器
            Random random = new Random();
            try
            {
                g.Clear(Color.White);
                ///繪制圖片的干擾線
                int x1, x2, y1, y2;
                for (int i = 0; i < IMAGELINENUMBER; i++)
                {
                    x1 = random.Next(image.Width);
                    x2 = random.Next(image.Height);
                    y1 = random.Next(image.Width);
                    y2 = random.Next(image.Height);
                }

                ///繪制驗證碼
                Font font = new Font("TaHoma", 12, FontStyle.Bold | FontStyle.Italic);
                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                g.DrawString(code, font, brush, 2.0f, 2.0f);


                ///畫圖片的前景噪音點
                int x, y;
                for (int i = 0; i < IMAGEPOINTNUMBER; i++)
                {
                    x = random.Next(image.Width);
                    y = random.Next(image.Height);
                    ///繪制點
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }

                ///
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

                ///
                MemoryStream ms = new MemoryStream();
                image.Save(ms, ImageFormat.Gif);


                ///
                Response.ClearContent();
                Response.ContentType = "image/Gif";
                Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }


        protected override void OnLoad(EventArgs e)
        {
            CreateValidateImage(length);
        }
        public void CreateValidateImage(int length)
        {
            code = CreateCode(length);
            CreateValidateImage(code);
        }
    }
}