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[ASP.net教程]图形验证码的生成(数字和英文大小写)和提交验证


最初接触时,感觉很好玩,然后就自己研究了下,做了个demo,然后整理下,下次可以直接使用啦,英文大小写,点击可以切换

上代码了。。。。

页面代码:

  <img id="Img" src="http://www.cnblogs.com//Login/GetCheckCode" />

  这个是页面JQuery点击更换方法

  $("#Img").click(function () {
    //this.src = "/Login/GetCheckCode?time="+(new Date()).getTime();   //这个也可以的

    //$("#Img").attr("src", "/Login/GetCheckCode?"+Math.random());

    $("#Img").attr("src", "/Login/GetCheckCode?time=" + (new Date()).getTime());

    注意:src后面加个time的时间参数,是为了再次加载验证码,否则加载不了。

    网上的解释:服务器端编写好生成验证码的方法,由于客户端浏览器会缓存URL相同的资源,可以使用随机数/或者时间来重新请求:
  });

后台代码:

    public ActionResult GetCheckCode()
    {
      string code = GenerateCheckCodes(4);
      Session["ValidateCode"] = code;
      byte[] bytes = CreateCheckCodeImage(code);
      return File(bytes, @"image/jpeg");
    }

    private string GenerateCheckCodes(int iCount)
    {
      char[] oCharacter = {'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'
            //'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'
              };
      //int number;
      string checkCode = String.Empty;
      int iSeed = DateTime.Now.Millisecond;
      System.Random random = new Random(iSeed);
      for (int i = 0; i < iCount; i++)
      {
        checkCode += oCharacter[random.Next(oCharacter.Length)];

        //纯数字
        //number = random.Next(10);
        //number = oCharacter[random.Next(oCharacter.Length)];
        //checkCode += number.ToString();
      }
      return checkCode;
    }

    private byte[] CreateCheckCodeImage(string checkCode)
    {
      if (checkCode == null || checkCode.Trim() == String.Empty)
      {
        return null;
      }
      int iWordWidth = 20;
      int iImageWidth = checkCode.Length * iWordWidth;
      Bitmap image = new Bitmap(iImageWidth, 30);
      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);

        //画图片的背景噪音点
        for (int i = 0; i < 20; 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);
        }

        //画图片的背景噪音线
        for (int i = 0; i < 2; i++)
        {
          int x1 = 0;
          int x2 = image.Width;
          int y1 = random.Next(image.Height);
          int y2 = random.Next(image.Height);
          if (i == 0)
          {
            g.DrawLine(new Pen(Color.Gray, 2), x1, y1, x2, y2);
          }

        }
        for (int i = 0; i < checkCode.Length; i++)
        {

           string Code = checkCode[i].ToString();
           int xLeft = iWordWidth * (i);
          random = new Random(xLeft);
          int iSeed = DateTime.Now.Millisecond;
          int iValue = random.Next(iSeed) % 4;
          if (iValue == 0)
          {
            Font font = new Font("Arial", 16, (FontStyle.Bold | System.Drawing.FontStyle.Italic));
            Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);
            LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.Red, 1.5f, true);
            g.DrawString(Code, font, brush, xLeft, 2);
          }
          else if (iValue == 1)
          {
            Font font = new System.Drawing.Font("楷体", 16, (FontStyle.Bold));
            Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);
            LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.DarkRed, 1.3f, true);
            g.DrawString(Code, font, brush, xLeft, 2);
          }
          else if (iValue == 2)
          {
            Font font = new System.Drawing.Font("宋体", 16, (System.Drawing.FontStyle.Bold));
            Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);
            LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Green, Color.Blue, 1.2f, true);
            g.DrawString(Code, font, brush, xLeft, 2);
          }
          else if (iValue == 3)
          {
            Font font = new System.Drawing.Font("黑体", 16, (System.Drawing.FontStyle.Bold |       

            System.Drawing.FontStyle.Bold));
            Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);
            LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.Green, 1.8f, true);
            g.DrawString(Code, font, brush, xLeft, 2);
          }
        }
        ////画图片的前景噪音点 ---有无这段代码 貌似没啥变化
        for (int i = 0; i < 8; 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);
        MemoryStream ms = new MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        return ms.ToArray();
        //Response.ClearContent();
        //Response.ContentType = "image/jpeg";
        //Response.BinaryWrite(ms.ToArray());
      }
      finally
      {
        g.Dispose();
        image.Dispose();
    }
  }

好了,就到这里了,有问题或者不正确的可以指正,我每天都会看一次。谢谢,希望对你有帮助。

说一下,这个代码的格式化 ,太麻烦了,每次都要一行一行的tab键。