怎么用c#实现随机图片验证码的功能

[jiangmurong]

已知前台如下的HTML

<td align="right" width="100">
              <font color="#2E5A87">安全码</font>                                                             </td>
    <td  >
       <INPUT class=input style="WIDTH: 40px" maxLength=20 name=checkcode autocomplete="off">
	 <img align='absmiddle' src='Img.aspx' style='cursor:pointer;' alt='请输入图片验证码' onClick="this.src='Img.aspx'"> 
    </td>

请教哪位好心人，帮把代码贴出来

[sherry7923]

先随机生成几个数字，再制作成图片。
网上应该有资料的。
我这里没有源码。

[冰川711]

protected void Page_Load(object sender, EventArgs e)
    {

        string chkCode = string.Empty;

        //颜色列表，用于验证码、噪线、噪点
        Color[] color ={ Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange,

Color.Brown, Color.DarkBlue };

        //字体列表，用于验证码
        string[] font ={ "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh",

"PMingLiU", "Impact" };

        //验证码的字符集，去掉了一些容易混淆的字符
        char[] character ={ '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E',

'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };

        Random rnd = new Random();

        //生成验证码字符串
        for (int i = 0; i < 4; i++)
        {
            chkCode += character[rnd.Next(character.Length)];
        }

        //保存验证码的Cookie
        HttpCookie anycookie = new HttpCookie("validateCookie");

        anycookie.Values.Add("ChkCode", chkCode);

        HttpContext.Current.Response.Cookies["validateCookie"].Values["ChkCode"] = chkCode;

        Bitmap bmp = new Bitmap(150, 30);

        Graphics g = Graphics.FromImage(bmp);

        g.Clear(Color.White);

        //画噪线
        for (int i = 0; i < 3; i++)
        {
            int x1 = rnd.Next(150);
            int y1 = rnd.Next(30);
            int x2 = rnd.Next(150);
            int y2 = rnd.Next(30);
            Color clr = color[rnd.Next(color.Length)];
            g.DrawLine(new Pen(clr), x1, y1, x2, y2);
        }

        //画验证码字符串
        for (int i = 0; i < chkCode.Length; i++)
        {
            string fnt = font[rnd.Next(font.Length)];
            Font ft = new Font(fnt, 16);
            Color clr = color[rnd.Next(color.Length)];
            g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 20 +

20, (float)6);
        }

        //画噪点
        for (int i = 0; i < 50; i++)
        {
            int x = rnd.Next(bmp.Width);
            int y = rnd.Next(bmp.Height);
            Color clr = color[rnd.Next(color.Length)];
            bmp.SetPixel(x, y, clr);
        }
        //清除该页输出缓存，设置该页无缓存
        Response.Buffer = true;

        Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);

        Response.Expires = 0;

        Response.CacheControl = "no-cache";

        Response.AppendHeader("Pragma", "No-Cache");

        //将验证码图片写入内存流，并将其以"image/Png" 格式输出
        MemoryStream ms = new MemoryStream();

        try
        {
            bmp.Save(ms, ImageFormat.Png);
            Response.ClearContent();
            Response.ContentType = "image/Png";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            //显式释放资源
            bmp.Dispose();
            g.Dispose();
        }
        

    }

网上有很多的！！

[porschev]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
using System.Drawing;

public partial class checkCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string[] str = new string[4];
        string serverCode = "";
        //生成随机生成器 
        Random random = new Random();
        for (int i = 0; i < 4; i++)
        {
            str[i] = random.Next(10).ToString().Substring(0, 1);
        }
        CreateCheckCodeImage(str);
        foreach (string s in str)
        {
            serverCode += s;
        }
        Session["serverCode"] = serverCode;
    }

    private void CreateCheckCodeImage(string[] checkCode)
    {
        if (checkCode == null || checkCode.Length <= 0)
            return;

        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 32.5)), 30);
        System.Drawing.Graphics g = Graphics.FromImage(image);

        try
        {
            Random random = new Random();
            //清空图片背景色 
            g.Clear(Color.White);

            //画图片的背景噪音线 
            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);
            }

            //定义颜色
            Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
            //定义字体
            string[] f = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

            for (int k = 0; k <= checkCode.Length - 1; k++)
            {
                int cindex = random.Next(7);
                int findex = random.Next(5);

                Font drawFont = new Font(f[findex], 16, (System.Drawing.FontStyle.Bold));
                SolidBrush drawBrush = new SolidBrush(c[cindex]);

                float x = 5.0F;
                float y = 0.0F;
                float width = 20.0F;
                float height = 25.0F;
                int sjx = random.Next(10);
                int sjy = random.Next(image.Height - (int)height);

                RectangleF drawRect = new RectangleF(x + sjx + (k * 25), y + sjy, width, height);

                StringFormat drawFormat = new StringFormat();
                drawFormat.Alignment = StringAlignment.Center;

                g.DrawString(checkCode[k], drawFont, drawBrush, drawRect, drawFormat);
            }

            //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 
            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();
        }
    }

}

[jiangmurong]

我在网上找了很多，都是服务器端的，我要客户端的

[jiangmurong]

都没效果，前台的html要怎么写？

[蔡袅]

html的？估计是javascript的吧？网上也很多的。
不过 用js容易被破解 而且很慢 不建议用

[jiangmurong]

感谢15楼的解答，解决了

[昵称是可以中文吗]

[Quote=引用 15 楼 yayiba2020 的回复:]
实现原理还是很简单的，用一个文本框作为验证码。上面的代码没有上文本框设置为只读，重新发下：

HTML code

<html>
<head>
<style type="text/css">
.code{
background-image:url(code.jpg);
font-family:Arial;
font-style:italic;
color:Red;
bord……
[/Quote]
(⊙o⊙)，我试试看先

[jiangmurong]

可是验证码错误也可以登录进去！！
这个怎么回事

[yayiba2020]

修改一下验证按钮的点击事件就可以了，

//asp.net 按钮
 <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return validate();" />
//html按钮
        <input id="Button2" type="submit" onclick="return validate();" value="button" />

[jiangmurong]

[Quote=引用 19 楼 yayiba2020 的回复:]

修改一下验证按钮的点击事件就可以了，
HTML code

//asp.net 按钮
<asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return validate();" />
//html按钮
<input id="Button2" type="submit" onclick="return validate();" value="button" />

[/Quote]

我就是用 <input name="submint" type="submit" id="submint" onclick="validate();"/>

我没用服务器换件

[jiangmurong]

[Quote=引用 19 楼 yayiba2020 的回复:]

修改一下验证按钮的点击事件就可以了，
HTML code

//asp.net 按钮
<asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return validate();" />
//html按钮
<input id="Button2" type="submit" onclick="r……
[/Quote]

恩解决了

[jiangmurong]

[Quote=引用 6 楼 xx_mm 的回复:]

html的？估计是javascript的吧？网上也很多的。
不过 用js容易被破解 而且很慢 不建议用
[/Quote]

还是不会

[xzf_fancy]

2楼的正解

[jiangmurong]

[Quote=引用 9 楼 xzf_fancy 的回复:]

2楼的正解
[/Quote]

都是网上的吧

[jiangmurong]

[Quote=引用 9 楼 xzf_fancy 的回复:]

2楼的正解
[/Quote]

可是我的没效果

[d364644964a]

其实,验证码图片中,怎么设置噪点

[yayiba2020]

JS实现验证码：

<html>
<head>
<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 = 4;//验证码的长度
var checkCode = document.getElementById("checkCode");
checkCode.value = "";

var selectChar = new Array(2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z');

for(var i=0;i<codeLength;i++) {
   var charIndex = Math.floor(Math.random()*32);
   code +=selectChar[charIndex];
}
if(code.length != codeLength){
   createCode();
}
checkCode.value = code;
}

function validate () {
var inputCode = document.getElementById("input1").value.toUpperCase();

if(inputCode.length <=0) {
   alert("请输入验证码！");
   return false;
}
else if(inputCode != code ){
   alert("验证码输入错误！");
   createCode();
   return false;
}
else {
   alert("OK");
   return true;
}

}
</script>
</head>
<body onload="createCode();">
<input type="text" id="input1" />
<input type="text" id="checkCode" class="code" style="width: 55px" /> <a href="#" onclick="createCode()">看不清楚</a><br /><br />
<center><input id="Button1" onclick="validate();" type="button" value="确定" /></center>
<script></script>
</body>
</html>

[yayiba2020]

实现原理还是很简单的，用一个文本框作为验证码。上面的代码没有上文本框设置为只读，重新发下：

<html>
<head>
<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 = 4;//验证码的长度
var checkCode = document.getElementById("checkCode");
checkCode.readOnly = true;
checkCode.value = "";

var selectChar = new Array(2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z');

for(var i=0;i<codeLength;i++) {
   var charIndex = Math.floor(Math.random()*32);
   code +=selectChar[charIndex];
}
if(code.length != codeLength){
   createCode();
}
checkCode.value = code;
}

function validate () {
var inputCode = document.getElementById("input1").value.toUpperCase();

if(inputCode.length <=0) {
   alert("请输入验证码！");
   return false;
}
else if(inputCode != code ){
   alert("验证码输入错误！");
   createCode();
   return false;
}
else {
   alert("OK");
   return true;
}

}
</script>
</head>
<body onload="createCode();">
<input type="text" id="input1" />
<input type="text" id="checkCode"  class="code" style="width: 55px" /> <a href="#" onclick="createCode()">看不清楚</a><br /><br />
<center><input id="Button1" onclick="validate();" type="button" value="确定" /></center>
<script></script>
</body>
</html>