using System;using System.Web;using System.Drawing;using System.Security.Cryptography;namespace DotNet.Utilities{  /// <summary>  /// 驗證碼類  /// </summary>  public class Rand  {    #region 生成隨機數字    /// <summary>    /// 生成隨機數字    /// </summary>    /// <param name="length">生成長度</param>    public static string Number(int Length)    {      return Number(Length, false);    }    /// <summary>    /// 生成隨機數字    /// </summary>    /// <param name="Length">生成長度</param>    /// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>    public static string Number(int Length, bool Sleep)    {      if (Sleep) System.Threading.Thread.Sleep(3);      string result = "";      System.Random random = new Random();      for (int i = 0; i < Length; i++)      {        result += random.Next(10).ToString();      }      return result;    }    #endregion    #region 生成隨機字母與數字    /// <summary>    /// 生成隨機字母與數字    /// </summary>    /// <param name="IntStr">生成長度</param>    public static string Str(int Length)    {      return Str(Length, false);    }    /// <summary>    /// 生成隨機字母與數字    /// </summary>    /// <param name="Length">生成長度</param>    /// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>    public static string Str(int Length, bool Sleep)    {      if (Sleep) System.Threading.Thread.Sleep(3);      char[] Pattern = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };      string result = "";      int n = Pattern.Length;      System.Random random = new Random(~unchecked((int)DateTime.Now.Ticks));      for (int i = 0; i < Length; i++)      {        int rnd = random.Next(0, n);        result += Pattern[rnd];      }      return result;    }    #endregion    #region 生成隨機純字母隨機數    /// <summary>    /// 生成隨機純字母隨機數    /// </summary>    /// <param name="IntStr">生成長度</param>    public static string Str_char(int Length)    {      return Str_char(Length, false);    }    /// <summary>    /// 生成隨機純字母隨機數    /// </summary>    /// <param name="Length">生成長度</param>    /// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>    public static string Str_char(int Length, bool Sleep)    {      if (Sleep) System.Threading.Thread.Sleep(3);      char[] Pattern = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };      string result = "";      int n = Pattern.Length;      System.Random random = new Random(~unchecked((int)DateTime.Now.Ticks));      for (int i = 0; i < Length; i++)      {        int rnd = random.Next(0, n);        result += Pattern[rnd];      }      return result;    }    #endregion  }  /// <summary>  /// 驗證圖片類  /// </summary>  public class YZMHelper  {    #region 私有字段    private string text;    private Bitmap image;    private int letterCount = 4;  //驗證碼位數    private int letterWidth = 16; //單個字體的寬度范圍    private int letterHeight = 20; //單個字體的高度范圍    private static byte[] randb = new byte[4];    private static RNGCryptoServiceProvider rand = new RNGCryptoServiceProvider();    private Font[] fonts =   {    new Font(new FontFamily("Times New Roman"),10 +Next(1),System.Drawing.FontStyle.Regular),    new Font(new FontFamily("Georgia"), 10 + Next(1),System.Drawing.FontStyle.Regular),    new Font(new FontFamily("Arial"), 10 + Next(1),System.Drawing.FontStyle.Regular),    new Font(new FontFamily("Comic Sans MS"), 10 + Next(1),System.Drawing.FontStyle.Regular)  };    #endregion    #region 公有屬性    /// <summary>    /// 驗證碼    /// </summary>    public string Text    {      get { return this.text; }    }    /// <summary>    /// 驗證碼圖片    /// </summary>    public Bitmap Image    {      get { return this.image; }    }    #endregion    #region 構造函數    public YZMHelper()    {      HttpContext.Current.Response.Expires = 0;      HttpContext.Current.Response.Buffer = true;HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1);      HttpContext.Current.Response.AddHeader("pragma", "no-cache");      HttpContext.Current.Response.CacheControl = "no-cache";      this.text = Rand.Number(4);      CreateImage();    }    #endregion    #region 私有方法    /// <summary>    /// 獲得下一個隨機數    /// </summary>    /// <param name="max">最大值</param>    private static int Next(int max)    {      rand.GetBytes(randb);      int value = BitConverter.ToInt32(randb, 0);      value = value % (max + 1);      if (value < 0) value = -value;      return value;    }    /// <summary>    /// 獲得下一個隨機數    /// </summary>    /// <param name="min">最小值</param>    /// <param name="max">最大值</param>    private static int Next(int min, int max)    {      int value = Next(max - min) + min;      return value;    }    #endregion    #region 公共方法    /// <summary>    /// 繪制驗證碼    /// </summary>    public void CreateImage()    {      int int_ImageWidth = this.text.Length * letterWidth;      Bitmap image = new Bitmap(int_ImageWidth, letterHeight);      Graphics g = Graphics.FromImage(image);      g.Clear(Color.White);      for (int i = 0; i < 2; i++)      {        int x1 = Next(image.Width - 1);        int x2 = Next(image.Width - 1);        int y1 = Next(image.Height - 1);        int y2 = Next(image.Height - 1);        g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);      }      int _x = -12, _y = 0;      for (int int_index = 0; int_index < this.text.Length; int_index++)      {        _x += Next(12, 16);        _y = Next(-2, 2);        string str_char = this.text.Substring(int_index, 1);        str_char = Next(1) == 1 ? str_char.ToLower() : str_char.ToUpper();        Brush newBrush = new SolidBrush(GetRandomColor());        Point thePos = new Point(_x, _y);        g.DrawString(str_char, fonts[Next(fonts.Length - 1)], newBrush, thePos);      }      for (int i = 0; i < 10; i++)      {        int x = Next(image.Width - 1);        int y = Next(image.Height - 1);        image.SetPixel(x, y, Color.FromArgb(Next(0, 255), Next(0, 255), Next(0, 255)));      }      image = TwistImage(image, true, Next(1, 3), Next(4, 6));      g.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, (letterHeight - 1));      this.image = image;    }    /// <summary>    /// 字體隨機顏色    /// </summary>    public Color GetRandomColor()    {      Random RandomNum_First = new Random((int)DateTime.Now.Ticks);      System.Threading.Thread.Sleep(RandomNum_First.Next(50));      Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);      int int_Red = RandomNum_First.Next(180);      int int_Green = RandomNum_Sencond.Next(180);      int int_Blue = (int_Red + int_Green > 300) ? 0 : 400 - int_Red - int_Green;      int_Blue = (int_Blue > 255) ? 255 : int_Blue;      return Color.FromArgb(int_Red, int_Green, int_Blue);    }    /// <summary>    /// 正弦曲線Wave扭曲圖片    /// </summary>    /// <param name="srcBmp">圖片路徑</param>    /// <param name="bXDir">如果扭曲則選擇為True</param>    /// <param name="nMultValue">波形的幅度倍數，越大扭曲的程度越高,一般為3</param>    /// <param name="dPhase">波形的起始相位,取值區間[0-2*PI)</param>    public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)    {      double PI = 6.283185307179586476925286766559;      Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);      Graphics graph = Graphics.FromImage(destBmp);      graph.FillRectangle(new SolidBrush(Color.White), 0, 0, destBmp.Width, destBmp.Height);      graph.Dispose();      double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;      for (int i = 0; i < destBmp.Width; i++)      {        for (int j = 0; j < destBmp.Height; j++)        {          double dx = 0;          dx = bXDir ? (PI * (double)j) / dBaseAxisLen : (PI * (double)i) / dBaseAxisLen;          dx += dPhase;          double dy = Math.Sin(dx);          int nOldX = 0, nOldY = 0;          nOldX = bXDir ? i + (int)(dy * dMultValue) : i;          nOldY = bXDir ? j : j + (int)(dy * dMultValue);          Color color = srcBmp.GetPixel(i, j);          if (nOldX >= 0 && nOldX < destBmp.Width           && nOldY >= 0 && nOldY < destBmp.Height)          {            destBmp.SetPixel(nOldX, nOldY, color);          }        }      }      srcBmp.Dispose();      return destBmp;    }    #endregion  }}