ASP.NET生成随机验证码代码和看不清切换验证码的小结

经过亲自测试,本代码复制并按照说明,可以直接运行

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using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Drawing; using System.IO;

public partial class CheckCode : System.Web.UI.Page {     protected void Page_Load(object sender, EventArgs e)     {         this.CreateCheckCodeImage(GenerateCheckCode());     }

/// <summary>     /// 创建随机生成的验证码,可以为数字或字母     /// </summary>     /// <returns></returns>     private string GenerateCheckCode()     {         int number = 0;         char code;         string checkcode = string.Empty;

// 随机生成数字,并转换成5个数字或字母         System.Random random = new Random();         for (int i = 0; i < 5; i++)         {             number = random.Next();             if (number % 2 == 0)                 code = (char)('0' + (char)(number % 10)); // 数字             else                 code = (char)('A' + (char)(number % 26)); // 字母

            checkcode += code.ToString();         }         Response.Cookies.Add(new HttpCookie("CheckCode", checkcode));         return checkcode;     }

/// <summary>     /// 创建随机验证的图片,包括背景色和前景色     /// </summary>     /// <param name="checkcode"></param>     private void CreateCheckCodeImage(string checkcode)     {         if (checkcode == null || checkcode.Trim() == string.Empty)             return;

        Bitmap image = new Bitmap((int)Math.Ceiling((checkcode.Length * 12.8)), 24);         Graphics grp = Graphics.FromImage(image);

        try         { // 产生随机生成码             Random random = new Random();

// 清空图片背景色             grp.Clear(Color.White);

// 画图片的背景噪音线             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);

                grp.DrawLine(new Pen(Color.SpringGreen), x1, x2, y1, y2);             }             Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));             System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);             grp.DrawString(checkcode, font, brush, 2, 2);

// 画图片的前景噪音点             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             grp.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

            MemoryStream ms = new MemoryStream();             image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);             Response.ClearContent();             Response.ContentType = "image/Gif";             Response.BinaryWrite(ms.ToArray());         }         catch (System.Exception ex)         {             Response.Write(ex.Message);         }         finally         { // 清除类对象(Graphics和Bitmap)             grp.Dispose();             image.Dispose();             grp = null;             image = null;         }     } }

生成随机验证码的配置说明:

假如以上验证码生成器页面名为:CheckCode.aspx,那么在登录页面中使用“<IMG>” 这个 HTML 元素来显示生成的验证码图片:<IMG src="CheckCode.aspx">   在登录页面的登录按钮的处理事件中使用以下代码判断验证码:

private void btnLogin_Click(object sender, System.Web.UI.ImageClickEventArgs e)   { if(Request.Cookies["CheckCode"] == null)    {     lblMessage.Text = "您的浏览器设置已被禁用 Cookies,您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。";     lblMessage.Visible = true; return;    }

if(String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text, true) != 0)    {     lblMessage.Text = "验证码错误,请输入正确的验证码。";     lblMessage.Visible = true; return;    }

添加图片,便切换验证码设置:

<img src="CheckCode.aspx" alt="若看不清,点击更换一张!!" onclick="this.src=this.src+'?'" />

转载声明: 本文转自http://wyzhjmy.blog.163.com/blog/static/7234753520093353751852/

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另外,亦可参考:

无刷新更换验证码

现在越来越多的网站的注册、发布等页面都采用了防止一些恶意程序的图片验证码选项,不知道大家有没有碰到这样的情况,一个注册表单,填写了帐号信息、个人信息,最后一项的验证码太模糊了竟然看不清,只能是重新刷新整个页面来刷新图片验证码的内容,这是一个不良好的交互设计。参考了一些门户网站的方法,我的改进设计思路如下: 把验证码输入项放在表单的第一行;客户端可以在不刷新整个页面的情况下更新图片验证码的内容。 我们一般要插入验证码都是使用<img />标签,例如<img src="validate.aspx" />,其中validate.aspx是一个生成图片的程序文件。为了能够更新验证码的内容,可以在图片旁边加一个更新的链接,单击触发图片重载事件,完成图片验证码的更换。具体代码如下:

<a href="javascript:reloadcode();" title="更换一张验证码图片"><img src="validate.aspx" id="safecode" alt="看不清,请换一张" /></a> <a href="javascript:reloadcode();" title="更换一张验证码图片">看不清,请换一张</a>

<script language="JavaScript"> function reloadcode()

{      document.getElementById('safecode').src = 'validate.aspx?' + Math.random(); }

</script>

注意:在reloadcode函数中,我们在code.asp后面加了一个随机参数,这样每次的链接地址都不一样,从而达到更新的目的。

<img src="validate.aspx"id="safecode" border="0" style="cursor:pointer;" onClick="this.src='validate.aspx?t='+Math.random()" alt="点击更换验证码">

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无刷新更换验证码

<script language ="javascript" type ="text/javascript"> function reloadcode() { document.getElementById('safecode').src = 'test.aspx?' + Math.random(); } script> <a href="javascript:reloadcode();" title="更换一张验证码图片"> <IMG src="test.aspx" id="safecode" alt="看不清,点击换张验证码">a> 在reloadcode函数中,我们在code.asp后面加了一个随机参数,这样每次的链接地址都不一样,从而达到更新的目的。

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    <img src="manage_product_checkCode.aspx" id="safecode" alt="看不清,点击换张验证码"/>     <a href="javascript:reloadcode()" title="更换一张验证码图片">更换一张验证码图片     </a> 

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转载声明: 本文转自http://czm600604604.blog.163.com/blog/static/8252068200981091443438/

无刷新更换验证码

页面中代码

<script language="javascript">       function change()       {           var img =document.getElementById("Image1");           img.src=img.src+'?';       } </script>

<img id="Image1" src="Image.aspx"/><a href="javascript:change();">看不清,换一张</a>

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图形验证码+“看不清楚换一张”

Image.aspx.cs 中代码

using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Drawing; using System.Drawing.Text; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.Drawing.Design;

//生成随机字符串 public partial class Image : System.Web.UI.Page {     private string CreateRandomNum(int NumCount)     {         string allChar = "0,1,2,3,4,5,6,7,8,9";         string[] allCharArray = allChar.Split(',');         string randomNum = "";         int temp = +1;         Random rand = new Random();         for (int i = 0; i < NumCount; i++)         {             if (temp != -1)             {                 rand = new Random(temp * ((int)DateTime.Now.Ticks));             }             int t = rand.Next(10);             if (temp == t)             {                 return CreateRandomNum(NumCount);             }             temp = t;             randomNum += allCharArray[t];         }         return randomNum;     } //生成图片     private void CreateImage(string validateNum)     {         if (validateNum == null || validateNum.Trim() == String.Empty)             return;         System.Drawing.Bitmap image = new System.Drawing.Bitmap(validateNum.Length * 12 + 10, 22);         Graphics g = Graphics.FromImage(image);         try         {             Random random = new Random();             g.Clear(Color.White);             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, x2, y1, y2);             }             Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));             System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);             g.DrawString(validateNum, font, brush, 2, 2);             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()));             }             g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);             System.IO.MemoryStream ms = new System.IO.MemoryStream();             image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);             Response.ClearContent();             Response.ContentType = "image/Gif";             Response.BinaryWrite(ms.ToArray());         }         finally         {             g.Dispose();             image.Dispose();         }     }     protected void Page_Load(object sender, EventArgs e)     {         if (!IsPostBack)         {             string validateNum = CreateRandomNum(4);             CreateImage(validateNum);             Session["ValidateNum"] = validateNum;         }         } }

页面中代码

<script language="javascript">       function change()       {           var img =document.getElementById("Image1");           img.src=img.src+'?';       } </script>

<img id="Image1" src="Image.aspx"/><a href="javascript:change();">看不清,换一张</a>

转载声明: 本文转自http://zzpdownload.blog.163.com/blog/static/83231134200912643320729/

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Javascript 验证码(尚未验证)

需要用到验证码,突然想能否用js做验证码呢? 当然js不能作图,但是可以用js模拟做验证码的 于是花了20分钟按照我的想法尝试做,最后做出来比我想象中的效果还要好,呵呵 先贴个图看看代码:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>无标题页</title>
    <style type="text/css">

        .code
        {
            background-image:url(code.jpg);
            font-family:Arial;
            font-style:italic;
            color:Red;
            border:0;
            padding:2px 3px;
            letter-spacing:3px;
            font-weight:bolder;
        }
        .unchanged
        {
            border:0;
        }
    
</style>
    <script language="javascript" type="text/javascript">
var code ; //在全局 定义验证码
     function createCode()
     { 
       code = "";
       var codeLength = 6;//验证码的长度
       var checkCode = document.getElementById("checkCode");
       var selectChar = new Array(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');//所有候选组成验证码的字符,当然也可以用中文的
        
       for(var i=0;i<codeLength;i++)
       {
      
        
       var charIndex = Math.floor(Math.random()*36);
       code +=selectChar[charIndex];
       
       
       }
//       alert(code);
       if(checkCode)
       {
         checkCode.className="code";
         checkCode.value = code;
       }
       
     }
     
      function validate ()
     {
       var inputCode = document.getElementById("input1").value;
       if(inputCode.length <=0)
       {
           alert("请输入验证码!");
       }
       else if(inputCode != code )
       {
          alert("验证码输入错误!");
          createCode();//刷新验证码
       }
       else
       {
         alert("^-^ OK");
       }
       
       }
</script>
</head>
<body>
<form  action="#">
     <input  type="text"  onclick="createCode()" id="input1" />
    
    <input type="text"  id="checkCode" class="unchanged" style="width: 80px"  /><br />
    <input id="Button1"  onclick="validate();" type="button" value="确定" /> 
</form>
</body>
</html>

转载声明: 本文转自http://www.chenjiliang.com/Article/View.aspx?ArticleID=5449

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