C#生成随机验证码

        

可以生成验证码类型有“字母字符串” 、“常用的汉字”、“简单的数学运算”。生成的验证码图片有jpeg和gif两种格式。

生成随机验证码包括数字字母和汉字两种形式,汉字形式利用GB2312编码表生成而且是常用的汉字。

GB2312 字符编码分布表：

分区范围	符号类型
第01区	中文标点、数学符号以及一些特殊字符
第02区	各种各样的数学序号
第03区	全角西文字符
第04区	日文平假名
第05区	日文片假名
第06区	希腊字母表
第07区	俄文字母表
第08区	中文拼音字母表
第09区	制表符号
第10－15区	无字符
第16－55区	一级汉字（以拼音字母排序）
第56－87区	二级汉字（以部首笔画排序）
第88－94区	无字符

 public class VerificationCode
  {

    //产生验证码的字符集
    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" };
    //产生验证码的算术符号
    private static string[] ArithmeticSymbol = new string[] { "＋", "－", "×", "÷" };
    //64位图片字符串开头描述
    private const string imageStr = "data:image/{0};base64,";

    ///<summary>
    ///生成随机验证码（数字字母）
    ///</summary>
    ///<param name="length">验证码的长度</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>
    /// 生成随机验证码（常用汉字）
    /// </summary>
    /// <param name="length">要产生常用汉字的个数</param>
    /// <returns></returns>
    public static string CreateValidateChinese(int length)
    {
      /*gb2312中文编码表由区码和位码表示*/
      string randomCode = "";
      Random rand = new Random();
      Encoding encoding = Encoding.GetEncoding("gb2312");//从gb2312中文编码表提取汉字
      for (int i = 0; i < length; i++)
      {
        int regionCode = rand.Next(16, 56); // 获取区码(常用汉字的区码范围为16-55)    
        int locationCode = rand.Next(1, (regionCode == 55 ? 90 : 95));// 获取位码(位码范围为1-94 由于55区的90,91,92,93,94为空,故将其排除)

        randomCode += encoding.GetString(new byte[] { (byte)(regionCode + 160), (byte)(locationCode + 160) });//区码位码分别加上A0H（160）的方法转换为存储码
      }
      return randomCode;
    }

    ///<summary>
    ///生成随机验证码（算术等式）
    ///</summary>
    ///<param name="length">验证码的长度</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])//减
      {
        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>
    ///创建验证码的图片
    ///</summary>
    ///<param name="bitmapParam">验证码参数</param>
    ///<param name="isGif">Gif样式</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 绘制干扰线

      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 计算干扰点坐标

      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 根据RECT计算文本字体大小

      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 计算每一帧文字坐标


        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 绘制每一帧文字坐标

        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) //画图片的前景干扰点
            {
              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>
    ///创建验证码的图片
    ///</summary>
    ///<param name="bitmapParam">验证码参数</param>
    ///<param name="isGif">Gif样式</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>
    ///创建验证码的图片
    ///</summary>
    ///<param name="bitmapParam">验证码参数</param>
    ///<param name="isGif">Gif样式</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>
    ///获取数组指定范围字符 
    /// </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>
    /// 计算
    /// </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])//减
      {
        return value1 - value2;
      }
      else if (type == ArithmeticSymbol[2])//乘
      {
        return value1 * value2;
      }
      else
      {
        return value1 / value2;
      }
    }

    /// <summary>
    /// 干扰点
    /// </summary>
    private class Dot
    {
      public Point gyd;
      public Color color;
    }

    /// <summary>
    /// 图片帧
    /// </summary>
    private class BitmapFrame
    {
      /// <summary>
      /// 帧
      /// </summary>
      public Bitmap frame;
      public float x;
      public float y;
      public float z_width;
    }

    /// <summary>
    /// 验证码（算术等式）
    /// </summary>
    public class ArithmeticEquation
    {
      /// <summary>
      /// 算术等式
      /// </summary>
      public List<string> text;
      /// <summary>
      /// 算术值
      /// </summary>
      public string value;
    }

    /// <summary>
    /// Gif帧类型
    /// </summary>
    public enum GifFrameType
    {
      /// <summary>
      /// 每个字符一帧
      /// </summary>
      EveryFrame,
      /// <summary>
      /// 全部字符一帧
      /// </summary>
      FullFrame
    }

    /// <summary>
    /// 验证码参数
    /// </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>
      /// 验证码字符集
      /// </summary>
      public List<string> textarr;
      /// <summary>
      /// 验证码图片宽
      /// </summary>
      public int width = 120;
      /// <summary>
      /// 验证码图片高
      /// </summary>
      public int height = 50;

      /// <summary>
      /// 图片背景颜色
      /// </summary>
      public Color backColor = Color.White;

      /// <summary>
      /// 字体
      /// </summary>
      public string fontName = "微软雅黑";

      /// <summary>
      /// 字体画笔颜色开始
      /// </summary>
      public Color fontBrushStrat = Color.FromArgb(193, 0, 91);

      /// <summary>
      /// 字体画笔颜色结束
      /// </summary>
      public Color fontBrushEnd = Color.FromArgb(136, 193, 0);

      /// <summary>
      /// 验证码字体样式
      /// </summary>
      public FontStyle fontStyle = FontStyle.Bold | FontStyle.Italic;
    }

    /// <summary>
    /// Gif样式
    /// </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动画
      /// </summary>
      public bool IsGif = false;
      /// <summary>
      ///  Gif帧类型
      /// </summary>
      public GifFrameType FrameType = GifFrameType.EveryFrame;
      /// <summary>
      /// 帧之间的延迟(毫秒)
      /// </summary>
      public int Delay = 500;
      /// <summary>
      /// GIF重复计数(0表示永久)
      /// </summary>
      public int Repeat = 0;
    }
  }

 源码下载地址：CSharp随机验证码.zip