C#生成隨機驗證碼

        

可以生成驗證碼類型有“字母字符串” 、“常用的漢字”、“簡單的數學運算”。生成的驗證碼圖片有jpeg和gif兩種格式。

生成隨機驗證碼包括數字字母和漢字兩種形式,漢字形式利用GB2312編碼表生成而且是常用的漢字。

GB2312 字符編碼分布表：

分區范圍	符號類型
第01區	中文標點、數學符號以及一些特殊字符
第02區	各種各樣的數學序號
第03區	全角西文字符
第04區	日文平假名
第05區	日文片假名
第06區	希臘字母表
第07區	俄文字母表
第08區	中文拼音字母表
第09區	制表符號
第10－15區	無字符
第16－55區	一級漢字（以拼音字母排序）
第56－87區	二級漢字（以部首筆畫排序）
第88－94區	無字符

 public class VerificationCode
  {

    //產生驗證碼的字符集
    private static string[] ValidateCharArray = new string[] { "2", "3", "4", "5", "6", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "M", "N", "P", "R", "S", "U", "W", "X", "Y", "a", "b", "c", "d", "e", "f", "g", "h", "j", "k", "m", "n", "p", "r", "s", "u", "w", "x", "y" };
    //產生驗證碼的算術符號
    private static string[] ArithmeticSymbol = new string[] { "＋", "－", "×", "÷" };
    //64位圖片字符串開頭描述
    private const string imageStr = "data:image/{0};base64,";

    ///<summary>
    ///生成隨機驗證碼（數字字母）
    ///</summary>
    ///<param name="length">驗證碼的長度</param>
    ///<returns></returns>
    public static string CreateValidateNumber(int length)
    {
      string randomCode = "";
      int temp = -1;

      Random rand = new Random();
      for (int i = 0; i < length; i++)
      {
        if (temp != -1)
        {
          rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
        }
        int t = rand.Next(ValidateCharArray.Length);
        if (temp != -1 && temp == t)
        {
          return CreateValidateNumber(length);
        }
        temp = t;
        randomCode += ValidateCharArray[t];
      }
      return randomCode;
    }

    /// <summary>
    /// 生成隨機驗證碼（常用漢字）
    /// </summary>
    /// <param name="length">要產生常用漢字的個數</param>
    /// <returns></returns>
    public static string CreateValidateChinese(int length)
    {
      /*gb2312中文編碼表由區碼和位碼表示*/
      string randomCode = "";
      Random rand = new Random();
      Encoding encoding = Encoding.GetEncoding("gb2312");//從gb2312中文編碼表提取漢字
      for (int i = 0; i < length; i++)
      {
        int regionCode = rand.Next(16, 56); // 獲取區碼(常用漢字的區碼范圍為16-55)    
        int locationCode = rand.Next(1, (regionCode == 55 ? 90 : 95));// 獲取位碼(位碼范圍為1-94 由於55區的90,91,92,93,94為空,故將其排除)

        randomCode += encoding.GetString(new byte[] { (byte)(regionCode + 160), (byte)(locationCode + 160) });//區碼位碼分別加上A0H（160）的方法轉換為存儲碼
      }
      return randomCode;
    }

    ///<summary>
    ///生成隨機驗證碼（算術等式）
    ///</summary>
    ///<param name="length">驗證碼的長度</param>
    ///<returns></returns>
    public static ArithmeticEquation CreateValidateArithmetic()
    {
      Random rand = new Random();
      ArithmeticEquation ai = new ArithmeticEquation();
      ai.text = new List<string>();
      ai.text.Add("");
      ai.text.Add("");
      ai.text.Add("");
      ai.text.Add("＝");

      ai.text[1] = ArithmeticSymbol[rand.Next(0, 4)];

      if (ai.text[1] == ArithmeticSymbol[0])//加
      {
        int len = rand.Next(1, 3);
        if (len == 1)
        {
          ai.text[0] = rand.Next(0, 10).ToString();
        }
        else
        {
          ai.text[0] = rand.Next(1, 10).ToString();
          ai.text[0] += rand.Next(0, 10).ToString();
        }

        if (len == 1)
        {
          ai.text[2] = rand.Next(1, 10).ToString();
          ai.text[2] += rand.Next(0, 10).ToString();
        }
        else
        {
          ai.text[2] = rand.Next(0, 10).ToString();
        }
      }
      else if (ai.text[1] == ArithmeticSymbol[1])//減
      {
        int len = rand.Next(1, 3);
        if (len == 1)
        {
          ai.text[0] = rand.Next(0, 10).ToString();
        }
        else
        {
          ai.text[0] = rand.Next(1, 10).ToString();
          ai.text[0] += rand.Next(0, 10).ToString();
        }

        if (len == 1)
        {
          ai.text[2] = rand.Next(0, int.Parse(ai.text[0]) + 1).ToString();
        }
        else
        {
          ai.text[2] = rand.Next(0, 10).ToString();
        }
      }
      else if (ai.text[1] == ArithmeticSymbol[2])//乘
      {
        ai.text[0] = rand.Next(1, 10).ToString();

        ai.text[2] = rand.Next(1, 10).ToString();
      }
      else
      {
        ai.text[2] = rand.Next(1, 10).ToString();

        ai.text[0] = (int.Parse(ai.text[2]) * rand.Next(1, 10)).ToString();

      }

      ai.value = calculate(ai.text[1], int.Parse(ai.text[0]), int.Parse(ai.text[2])).ToString();

      return ai;
    }

    ///<summary>
    ///創建驗證碼的圖片
    ///</summary>
    ///<param name="bitmapParam">驗證碼參數</param>
    ///<param name="isGif">Gif樣式</param>
    public static Bitmap CreateValidateImage(BitmapParam bitmapParam, BitmapStyle bitmapStyle)
    {
      Bitmap result = null;
      Random random = new Random();
      string text = String.Concat(bitmapParam.textarr);
      int count = bitmapParam.textarr.Count;

      Bitmap bmp_template = new Bitmap(bitmapParam.width, bitmapParam.height);
      Graphics g_template = Graphics.FromImage(bmp_template);
      #region 繪制干擾線

      g_template.Clear(bitmapParam.backColor);
      using (Pen pen = new Pen(Color.Silver))
      {
        for (int i = 0; i < 25; i++)
        {
          int x1 = random.Next(bmp_template.Width);
          int x2 = random.Next(bmp_template.Width);
          int y1 = random.Next(bmp_template.Height);
          int y2 = random.Next(bmp_template.Height);
          g_template.DrawLine(pen, x1, y1, x2, y2);
        }
      }

      #endregion

      List<Dot> dotlist = new List<Dot>();
      #region 計算干擾點坐標

      for (int i = 0; i < 100; i++)
      {
        dotlist.Add(new Dot() { gyd = new Point(random.Next(bmp_template.Width), random.Next(bmp_template.Height)), color = Color.FromArgb(random.Next()) });
      }
      #endregion

      int defaultfontsize = 7;
      int defaultfontmargin = 3;
      #region 根據RECT計算文本字體大小

      for (int i = defaultfontsize; i < 300; i++)
      {
        using (Font f = new Font(bitmapParam.fontName, i, bitmapParam.fontStyle))
        {
          if (g_template.MeasureString(text, f).Width > bitmapParam.width - defaultfontmargin * 2)
          {
            defaultfontsize = i;
            break;
          }
        }
      }
      for (int i = defaultfontsize; i > 1; i--)
      {
        using (Font f = new Font(bitmapParam.fontName, i, bitmapParam.fontStyle))
        {
          if (g_template.MeasureString(text, f).Height < bitmapParam.height - defaultfontmargin * 2)
          {
            defaultfontsize = i;
            break;
          }
        }
      }

      #endregion
      Font text_font = new Font(bitmapParam.fontName, defaultfontsize, bitmapParam.fontStyle);
      SizeF text_size = g_template.MeasureString(text, text_font);
      LinearGradientBrush text_brush = new LinearGradientBrush(new Rectangle(0, 0, bmp_template.Width, bmp_template.Height), Color.FromArgb(193, 0, 91), Color.FromArgb(136, 193, 0), 1.2f, true);

      float x_align = ((float)bitmapParam.width - text_size.Width) / 2.0f;
      float y_align = ((float)bitmapParam.height - text_size.Height) / 2.0f;
      List<BitmapFrame> bitmapframelist = new List<BitmapFrame>();
      if (!bitmapStyle.IsGif || (bitmapStyle.IsGif && bitmapStyle.FrameType == GifFrameType.FullFrame))
      {
        bitmapframelist.Add(new BitmapFrame() { frame = (Bitmap)bmp_template.Clone() });
        using (Graphics graphics = Graphics.FromImage(bitmapframelist[0].frame))
        {
          graphics.DrawString(text, text_font, text_brush, x_align, y_align);
          foreach (Dot dot in dotlist)
          {
            bitmapframelist[0].frame.SetPixel(dot.gyd.X, dot.gyd.Y, dot.color);
          }
        }
        if (!bitmapStyle.IsGif)
        {
          result = bitmapframelist[0].frame;
        }
        else
        {
          GifCore gif = new GifCore(bitmapStyle.Delay, bitmapStyle.Repeat);
          foreach (Dot dot in dotlist)
          {
            bmp_template.SetPixel(dot.gyd.X, dot.gyd.Y, dot.color);
          }
          gif.AddFrame(bmp_template, delay: -1);
          gif.AddFrame((Image)bitmapframelist[0].frame, delay: -1);
          result = gif.Finish();
          foreach (BitmapFrame item in bitmapframelist)
          {
            item.frame.Dispose();
          }
        }
      }
      else
      {
        for (int i = 0; i < count; i++)
        {
          bitmapframelist.Add(new BitmapFrame() { frame = (Bitmap)bmp_template.Clone() });
        }

        #region 計算每一幀文字坐標


        if (count == 1)
        {
          bitmapframelist[0].x = x_align;
          bitmapframelist[0].y = y_align;
          bitmapframelist[0].z_width = 0;
        }
        else
        {
          for (int k = 0; k < count; k++)
          {
            if (k == 0)
            {
              bitmapframelist[0].x = x_align;
              bitmapframelist[0].y = y_align;
              bitmapframelist[0].z_width = g_template.MeasureString(GetScopeString(bitmapParam.textarr, 0, k + 2), text_font).Width - g_template.MeasureString(bitmapParam.textarr[k + 1], text_font).Width;
            }
            else
            {
              bitmapframelist[k].x = bitmapframelist[k - 1].x + bitmapframelist[k - 1].z_width;
              bitmapframelist[k].y = y_align;
              bitmapframelist[k].z_width = g_template.MeasureString(GetScopeString(bitmapParam.textarr, 0, k + 1), text_font).Width - g_template.MeasureString(GetScopeString(bitmapParam.textarr, 0, k), text_font).Width;
            }
          }
        }

        #endregion

        #region 繪制每一幀文字坐標

        for (int k = 0; k < count; k++)
        {
          using (Graphics graphics = Graphics.FromImage(bitmapframelist[k].frame))
          {
            graphics.DrawString(bitmapParam.textarr[k], text_font, text_brush, bitmapframelist[k].x, bitmapframelist[k].y);
            foreach (Dot dot in dotlist) //畫圖片的前景干擾點
            {
              bitmapframelist[k].frame.SetPixel(dot.gyd.X, dot.gyd.Y, dot.color);
            }
          }
        }

        #endregion

        #region 生成Gif

        GifCore gif = new GifCore(bitmapStyle.Delay, bitmapStyle.Repeat);
        if (count == 1)
        {
          foreach (Dot dot in dotlist)
          {
            bmp_template.SetPixel(dot.gyd.X, dot.gyd.Y, dot.color);
          }
          gif.AddFrame(bmp_template, delay: -1);
        }
        foreach (BitmapFrame item in bitmapframelist)
        {
          gif.AddFrame((Image)item.frame, delay: -1);
        }
        result = gif.Finish();
        foreach (BitmapFrame item in bitmapframelist)
        {
          item.frame.Dispose();
        }

        #endregion
      }

      text_font.Dispose();
      text_brush.Dispose();
      g_template.Dispose();
      bmp_template.Dispose();
      return result;

    }

    //
    ///<summary>
    ///創建驗證碼的圖片
    ///</summary>
    ///<param name="bitmapParam">驗證碼參數</param>
    ///<param name="isGif">Gif樣式</param>
    public static byte[] CreateValidateImageBytes(BitmapParam bitmapParam, BitmapStyle bitmapStyle)
    {
      using (MemoryStream ms = new MemoryStream())
      {
        Bitmap image = CreateValidateImage(bitmapParam, bitmapStyle);
        image.Save(ms, bitmapStyle.IsGif ? ImageFormat.Gif : ImageFormat.Jpeg);
        if (image != null)
          image.Dispose();
        return ms.ToArray();
      }
    }

    //
    ///<summary>
    ///創建驗證碼的圖片
    ///</summary>
    ///<param name="bitmapParam">驗證碼參數</param>
    ///<param name="isGif">Gif樣式</param>
    public static string CreateValidateImageBase64String(BitmapParam bitmapParam, BitmapStyle bitmapStyle)
    {
      return String.Format(imageStr, bitmapStyle.IsGif ? "gif" : "jpeg") + Convert.ToBase64String(CreateValidateImageBytes(bitmapParam, bitmapStyle));
    }

    /// <summary>
    /// 拆分文本
    /// </summary>
    /// <param name="str"></param>
    /// <returns></returns>
    public static List<string> StringToArray(string str)
    {
      str = str.Trim();
      List<string> result = new List<string>();
      for (int i = 0; i < str.Length; i++)
      {
        result.Add(str.Substring(i, 1));
      }
      return result;
    }

    /// <summary>
    ///獲取數組指定范圍字符 
    /// </summary>
    /// <param name="arr"></param>
    /// <param name="start"></param>
    /// <param name="len"></param>
    /// <returns></returns>
    public static string GetScopeString(List<string> arr, int start, int len)
    {
      string result = String.Empty;
      for (int i = 0; i < len; i++)
      {
        result += arr[start + i];
      }
      return result;
    }

    /// <summary>
    /// 計算
    /// </summary>
    /// <param name="type"></param>
    /// <param name="value1"></param>
    /// <param name="value2"></param>
    /// <returns></returns>
    private static int calculate(string type, int value1, int value2)
    {
      if (type == ArithmeticSymbol[0])//加
      {
        return value1 + value2;
      }
      else if (type == ArithmeticSymbol[1])//減
      {
        return value1 - value2;
      }
      else if (type == ArithmeticSymbol[2])//乘
      {
        return value1 * value2;
      }
      else
      {
        return value1 / value2;
      }
    }

    /// <summary>
    /// 干擾點
    /// </summary>
    private class Dot
    {
      public Point gyd;
      public Color color;
    }

    /// <summary>
    /// 圖片幀
    /// </summary>
    private class BitmapFrame
    {
      /// <summary>
      /// 幀
      /// </summary>
      public Bitmap frame;
      public float x;
      public float y;
      public float z_width;
    }

    /// <summary>
    /// 驗證碼（算術等式）
    /// </summary>
    public class ArithmeticEquation
    {
      /// <summary>
      /// 算術等式
      /// </summary>
      public List<string> text;
      /// <summary>
      /// 算術值
      /// </summary>
      public string value;
    }

    /// <summary>
    /// Gif幀類型
    /// </summary>
    public enum GifFrameType
    {
      /// <summary>
      /// 每個字符一幀
      /// </summary>
      EveryFrame,
      /// <summary>
      /// 全部字符一幀
      /// </summary>
      FullFrame
    }

    /// <summary>
    /// 驗證碼參數
    /// </summary>
    public class BitmapParam
    {
      public BitmapParam()
      {

      }

      public BitmapParam(List<string> _textarr, int _width, int _height, Color _backColor, string _fontName, Color _fontBrushStrat, Color _fontBrushEnd, FontStyle _fontStyle)
      {
        this.textarr = _textarr;
        this.width = _width;
        this.height = _height;
        this.backColor = _backColor;
        this.fontName = _fontName;
        this.fontBrushStrat = _fontBrushStrat;
        this.fontBrushEnd = _fontBrushEnd;
        this.fontStyle = _fontStyle;
      }

      /// <summary>
      /// 驗證碼字符集
      /// </summary>
      public List<string> textarr;
      /// <summary>
      /// 驗證碼圖片寬
      /// </summary>
      public int width = 120;
      /// <summary>
      /// 驗證碼圖片高
      /// </summary>
      public int height = 50;

      /// <summary>
      /// 圖片背景顏色
      /// </summary>
      public Color backColor = Color.White;

      /// <summary>
      /// 字體
      /// </summary>
      public string fontName = "微軟雅黑";

      /// <summary>
      /// 字體畫筆顏色開始
      /// </summary>
      public Color fontBrushStrat = Color.FromArgb(193, 0, 91);

      /// <summary>
      /// 字體畫筆顏色結束
      /// </summary>
      public Color fontBrushEnd = Color.FromArgb(136, 193, 0);

      /// <summary>
      /// 驗證碼字體樣式
      /// </summary>
      public FontStyle fontStyle = FontStyle.Bold | FontStyle.Italic;
    }

    /// <summary>
    /// Gif樣式
    /// </summary>
    public class BitmapStyle
    {
      public BitmapStyle()
      {

      }

      public BitmapStyle(bool _IsGif, GifFrameType _FrameType, int _Delay, int _Repeat)
      {
        this.IsGif = _IsGif;
        this.FrameType = _FrameType;
        this.Delay = _Delay;
        this.Repeat = _Repeat;
      }

      /// <summary>
      /// 是否生成Gif動畫
      /// </summary>
      public bool IsGif = false;
      /// <summary>
      ///  Gif幀類型
      /// </summary>
      public GifFrameType FrameType = GifFrameType.EveryFrame;
      /// <summary>
      /// 幀之間的延遲(毫秒)
      /// </summary>
      public int Delay = 500;
      /// <summary>
      /// GIF重復計數(0表示永久)
      /// </summary>
      public int Repeat = 0;
    }
  }

 源碼下載地址：CSharp隨機驗證碼.zip