namespace QJW.VerifyCode{  //用法：  //public FileContentResult CreateValidate()  //{  //  ValidateCode vCode = new ValidateCode();  //  string code = vCode.CreateValidateCode(5);  //  Session["ValidateCode"] = code;  //  byte[] bytes = vCode.CreateValidateGraphic(code);  //  return File(bytes, "image/JPEG");  //}  public class ValidateCode  {    public ValidateCode()    {    }    /// <summary>    /// 驗證碼的最大長度    /// </summary>    public int MaxLength    {      get { return 10; }    }    /// <summary>    /// 驗證碼的最小長度    /// </summary>    public int MinLength    {      get { return 1; }    }    /// <summary>    /// 生成驗證碼    /// </summary>    /// <param name="length">指定驗證碼的長度</param>    /// <returns></returns>    public string CreateValidateCode(int length)    {      int[] randMembers = new int[length];      int[] validateNums = new int[length];      string validateNumberStr = "";      //生成起始序列值      int seekSeek = unchecked((int)DateTime.Now.Ticks);      Random seekRand = new Random(seekSeek);      int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);      int[] seeks = new int[length];      for (int i = 0; i < length; i++)      {        beginSeek += 10000;        seeks[i] = beginSeek;      }      //生成隨機數字      for (int i = 0; i < length; i++)      {        Random rand = new Random(seeks[i]);        int pownum = 1 * (int)Math.Pow(10, length);        randMembers[i] = rand.Next(pownum, Int32.MaxValue);      }      //抽取隨機數字      for (int i = 0; i < length; i++)      {        string numStr = randMembers[i].ToString();        int numLength = numStr.Length;        Random rand = new Random();        int numPosition = rand.Next(0, numLength - 1);        validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));      }      //生成驗證碼      for (int i = 0; i < length; i++)      {        validateNumberStr += validateNums[i].ToString();      }      return validateNumberStr;    }    /// <summary>    /// 創建驗證碼的圖片    /// </summary>    /// <param name="containsPage">要輸出到的page對象</param>    /// <param name="validateNum">驗證碼</param>    public byte[] CreateValidateGraphic(string validateCode)    {      Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);      Graphics g = Graphics.FromImage(image);      try      {        //生成隨機生成器        Random random = new Random();        //清空圖片背景色        g.Clear(Color.White);        //畫圖片的干擾線        for (int i = 0; i < 25; 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(new Pen(Color.Silver), x1, y1, x2, y2);        }        Font font = new Font("Arial", 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(validateCode, font, brush, 3, 2);        //畫圖片的前景干擾點        for (int i = 0; i < 100; 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);        //保存圖片數據        MemoryStream stream = new MemoryStream();        image.Save(stream, ImageFormat.Jpeg);        //輸出圖片流        return stream.ToArray();      }      finally      {        g.Dispose();        image.Dispose();      }    }    /// <summary>    /// 得到驗證碼圖片的長度    /// </summary>    /// <param name="validateNumLength">驗證碼的長度</param>    /// <returns></returns>    public static int GetImageWidth(int validateNumLength)    {      return (int)(validateNumLength * 12.0);    }    /// <summary>    /// 得到驗證碼的高度    /// </summary>    /// <returns></returns>    public static double GetImageHeight()    {      return 22.5;    }  }}

    public FileContentResult CreateValidate()    {      ValidateCode vCode = new ValidateCode();      string code = vCode.CreateValidateCode(5);      Session["ValidateCode"] = code;      byte[] bytes = vCode.CreateValidateGraphic(code);      return File(bytes, "image/JPEG");    }