Use of verification code class in asp.net mvc

This article mainly introduces the use of asp.net mvc verification code class in detail, which has certain reference value. Interested friends can refer to

Verification Code Class

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>
    /// 验证码的最大长度
    /// </summary>
    public int MaxLength
    {
      get { return 10; }
    }
    /// <summary>
    /// 验证码的最小长度
    /// </summary>
    public int MinLength
    {
      get { return 1; }
    }
    /// <summary>
    /// 生成验证码
    /// </summary>
    /// <param name="length">指定验证码的长度</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;
      }
      //生成随机数字
      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);
      }
      //抽取随机数字
      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));
      }
      //生成验证码
      for (int i = 0; i < length; i++)
      {
        validateNumberStr += validateNums[i].ToString();
      }
      return validateNumberStr;
    }
    /// <summary>
    /// 创建验证码的图片
    /// </summary>
    /// <param name="containsPage">要输出到的page对象</param>
    /// <param name="validateNum">验证码</param>
    public byte[] CreateValidateGraphic(string validateCode)
    {
      Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
      Graphics g = Graphics.FromImage(image);
      try
      {
        //生成随机生成器
        Random random = new Random();
        //清空图片背景色
        g.Clear(Color.White);
        //画图片的干扰线
        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);
        //画图片的前景干扰点
        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()));
        }
        //画图片的边框线
        g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
        //保存图片数据
        MemoryStream stream = new MemoryStream();
        image.Save(stream, ImageFormat.Jpeg);
        //输出图片流
        return stream.ToArray();
      }
      finally
      {
        g.Dispose();
        image.Dispose();
      }
    }
    /// <summary>
    /// 得到验证码图片的长度
    /// </summary>
    /// <param name="validateNumLength">验证码的长度</param>
    /// <returns></returns>
    public static int GetImageWidth(int validateNumLength)
    {
      return (int)(validateNumLength * 12.0);
    }
    /// <summary>
    /// 得到验证码的高度
    /// </summary>
    /// <returns></returns>
    public static double GetImageHeight()
    {
      return 22.5;
    }
  }
}

Usage

    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");
    }

HTML
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ViewJS

function reloadcode() {
    var verify = document.getElementById('safecode');
    verify.setAttribute('src', '/common/CreateValidate?' + Math.random());
  }

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