验证码session 的问题

[supersyd]

在第一次显示验证码的时候，session正常，点击<img>后，session 和图片的数字，0半秒左右后就不一致了。
很奇怪的问题
调用
<img id="checkcode" alt="点击更换验证码" width="72" height="24" src="inc/code.ashx" onclick="this.src='inc/code.ashx?rnd' + new Date().valueOf()" style="display:block" />

验证码文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.SessionState;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace PicManage.inc
{
/// <summary>
/// $codebehindclassname$ 的摘要说明
/// </summary>
public class code : IHttpHandler,IRequiresSessionState
{
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;

#region 验证码长度(默认4个验证码的长度)
int length = 4;
public int Length
{
get { return length; }
set { length = value; }
}
#endregion

#region 验证码字体大小(为了显示扭曲效果，默认14像素，可以自行修改)
int fontSize = 14;
public int FontSize
{
get { return fontSize; }
set { fontSize = value; }
}
#endregion

#region 边框补(默认1像素)
int padding = 1;
public int Padding
{
get { return padding; }
set { padding = value; }
}
#endregion

#region 是否输出燥点(默认输出)
bool chaos = true;
public bool Chaos
{
get { return chaos; }
set { chaos = value; }
}
#endregion

#region 输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get { return chaosColor; }
set { chaosColor = value; }
}
#endregion

#region 自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get { return backgroundColor; }
set { backgroundColor = value; }
}
#endregion

#region 自定义随机颜色数组
Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
public Color[] Colors
{
get { return colors; }
set { colors = value; }
}
#endregion

#region 自定义字体数组
string[] fonts = { "Arial", "Georgia" };
public string[] Fonts
{
get { return fonts; }
set { fonts = value; }
}
#endregion

#region 自定义随机码字符串序列(使用逗号分隔)
string codeSerial = "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";
public string CodeSerial
{
get { return codeSerial; }
set { codeSerial = value; }
}
#endregion


public void ProcessRequest(HttpContext context)
{
context.Session.Timeout = 20;
string code = CreateVerifyCode(4);
context.Session.Remove(code);
context.Session.Add("code",code);
CreateImageOnPage(code, context);

}


public string CreateVerifyCode(int codeLen)
{
if (codeLen == 0)
{
codeLen = Length;
}

string[] arr = CodeSerial.Split(',');

string code = "";

int randValue = -1;

Random rand = new Random(unchecked((int)DateTime.Now.Ticks));

for (int i = 0; i < codeLen; i++)
{
randValue = rand.Next(0, arr.Length - 1);
code += arr[randValue];
}
return code;
}



/// <summary>
/// 生成校验码图片
/// </summary>
/// <param name="code"></param>
/// <returns></returns>
public Bitmap CreateImageCode(string code)
{
int fSize = FontSize;
int fWidth = fSize + Padding;

int imageWidth = (int)(code.Length * fWidth) + 20 + Padding * 2;
int imageHeight = fSize +10;

System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);

Graphics g = Graphics.FromImage(image);

g.Clear(BackgroundColor);

Random rand = new Random();

//给背景添加随机生成的燥点
if (this.Chaos)
{

Pen pen = new Pen(ChaosColor, 0);
int c = Length * 10;

for (int i = 0; i < c; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);

g.DrawRectangle(pen, x, y, 1, 1);
}
}

int left = 0, top = 0, top1 = 1, top2 = 1;

int n1 = (imageHeight - FontSize - Padding * 2);
int n2 = n1 / 4;
top1 = n2;
top2 = n2 * 2;

Font f;
Brush b;

int cindex, findex;

//随机字体和颜色的验证码字符
for (int i = 0; i < code.Length; i++)
{
cindex = rand.Next(Colors.Length - 1);
findex = rand.Next(Fonts.Length - 1);

f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
b = new System.Drawing.SolidBrush(Colors[cindex]);

if (i % 2 == 1)
{
top = top2;
}
else
{
top = top1;
}

left = i * fWidth;

g.DrawString(code.Substring(i, 1), f, b, left, top);
}

//画一个边框 边框颜色为Color.Gainsboro
g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose();

//产生波形
int phase = (int)PI2 * 100;
image = TwistImage(image, true, 3, new Random().Next(0, phase) , 0.3f );

return image;
}

/// <summary>
/// 正弦曲线Wave扭曲图片
/// </summary>
/// <param name="srcBmp">图片路径</param>
/// <param name="bXDir">如果扭曲则选择为True</param>
/// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
/// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
/// <returns></returns>
public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase, float times)
{
int w = srcBmp.Width;
int h = srcBmp.Height;
System.Drawing.Bitmap destBmp = new Bitmap(w, h, PixelFormat.Format24bppRgb);

// 将位图背景填充为白色
using (System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp))
{
graph.Clear(Color.White);
}

double dBaseAxisLen = bXDir ? (double)h : (double)w;
BitmapData destData = destBmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.WriteOnly, destBmp.PixelFormat);
BitmapData srcData = srcBmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadOnly, srcBmp.PixelFormat);
byte[] rgbValues = new byte[3];
for (int i = 0; i < w; i++)
{
for (int j = 0; j < h; j++)
{
double dx = 0;
dx = bXDir ? (PI2 * (double)j * times) / dBaseAxisLen : (PI2 * (double)i * times) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);

// 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue);

if (nOldX >= 0 && nOldX < w
&& nOldY >= 0 && nOldY < h)
{
Marshal.Copy((IntPtr)((int)srcData.Scan0 + ((j * srcData.Stride) + (i * 3))), rgbValues, 0, 3);
Marshal.Copy(rgbValues, 0, (IntPtr)((int)destData.Scan0 + ((nOldY * destData.Stride) + (nOldX * 3))), 3);
}
}
}
destBmp.UnlockBits(destData);
srcBmp.UnlockBits(srcData);
if (srcBmp != null)
srcBmp.Dispose();
return destBmp;
}


public void CreateImageOnPage(string code, HttpContext context)
{
System.IO.MemoryStream ms = new System.IO.MemoryStream();
Bitmap image = this.CreateImageCode(code);

image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

context.Response.ClearContent();
context.Response.ContentType = "image/png";
context.Response.BinaryWrite(ms.GetBuffer());

ms.Close();
ms = null;
image.Dispose();
image = null;

context.Response.End();
}
public bool IsReusable
{
get
{
return false;
}
}
}
}

[myhope88]

如果一直这样子的话，应该是session没存对

[yingyuebingya]

<img id="checkcode" alt="点击更换验证码" width="72" height="24" src="inc/code.ashx" onclick="this.src='inc/code.ashx?rnd=' + new Date().valueOf()" style="display:block" />
搞不清楚，开始胡猜...

[zsuswy]

session存在什么地方？

[T_long]

调试一下，看每次刷新时是否存到了Session中

[sxiaohui8709253]

sission存验证码 可能会导致丢失，建议用cookie

[mngzilin]

懒得看了，

最大的错误之处在于ashx处理的过程在非UI线程内，无法正常访问Session，即使你继承了IRequiresSessionState 接口，即使有了Session操作。

解决办法：将ashx文件换成普通的aspx文件

[mngzilin]

不信的话，你可以做个简单的测试，在ashx文件中，添加一个Session键值，在page页面中是访问不到的，总是null，反之亦然。

[asharpnet]

跟下生成图片的Session

[初吻给了烟]

ASP.NET中无刷新验证码实现 收藏
Default.aspx页面代码view plaincopy to clipboardprint?<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Untitled Page</title> <script>function show(im) { im.src="Default2.aspx?"+new Date;//注意这里的new Date一定要加上，否则只会生成一次验证码 }</script> </head> <body> <form id="form1" runat="server"> <div> <img src="Default2.aspx" onclick ="show(this)" /> </div> </form> </body> </html> <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<title>Untitled Page</title>

<script>function show(im)

{

im.src="Default2.aspx?"+new Date;//注意这里的new Date一定要加上，否则只会生成一次验证码

}</script>

</head>

<body>

<form id="form1" runat="server">

<div>

<img src="Default2.aspx" onclick ="show(this)" />

</div>

</form>

</body>

</html>
Default2.cs代码 主要用来生成验证图片
view plaincopy to clipboardprint?
<FONT color=#000000>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.Drawing2D;



public partial class Default2 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

CreateCheckCodeImage(GenerateCheckCode());

}

/// <summary>

/// 生成随机校验码字符串

/// </summary>

/// <returns>生成的随机校验码字符串</returns>

public string GenerateCheckCode()

{

int number;

string strCode = string.Empty;

//随机数种子

Random radom = new Random();

for (int i = 0; i < 4; i++)

{

//随机的整数

number = radom.Next();

//字符从０－９，Ａ－Ｚ中随机产生，对应的ＡＳＣＩＩ码分别为48-57,65,90

number = number % 36;

if (number < 10)

{

number += 48;

}

else

{

number += 55;

}

strCode += ((char)number).ToString();

}

//在Cookie中保存校验码或Session中

Response.Cookies.Add(new HttpCookie("CheckCode", strCode));

return strCode;

}

/// <summary>

/// 根据校验码输出图片

/// </summary>

/// <param name="checkCode">产生的随机校验码</param>

public void CreateCheckCodeImage(string checkCode)

{

//若校验码为空，则直接返回

if (checkCode == null || checkCode.Trim() == string.Empty)

{

return;

}

//根据校验码的长度确定输出图片的长度

System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling(decimal.Parse((checkCode.Length * 15)+"")), 20);

//创建ＧＲＡＰＨＩＣＳ对象

System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);

try

{

//生成随机数种子

Random random = new Random();

//清空图片背景色

g.Clear(System.Drawing.Color.White);

//画图片的背景噪音线１０条

for (int i = 0; i < 10; i++)

{

//噪音线起点坐标（x1,y1），终点坐标（x2,y2）

int x1 = random.Next(image.Width);

int x2 = random.Next(image.Width);

int y1 = random.Next(image.Height);

int y2 = random.Next(image.Height);

//用银色画出噪音线

g.DrawLine(new System.Drawing.Pen(System.Drawing.Color.Silver), x1, y1, x2, y2);

}

//输出图片中校验码的字体：１２号Arial,粗斜体

System.Drawing.Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));

//线形渐变画刷

System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Color.Blue, System.Drawing.Color.Purple, 1.2f, true);

g.DrawString(checkCode, font, brush, 2, 3);

//画图片的前景噪音点５０个

for (int i = 0; i < 50; i++)

{

int x = random.Next(image.Width);

int y = random.Next(image.Height);

image.SetPixel(x, y, System.Drawing.Color.FromArgb(random.Next()));

}

//画图片的边框线

g.DrawRectangle(new System.Drawing.Pen(System.Drawing.Color.SaddleBrown), 0, 0, image.Width - 1, image.Height - 1);

//创建内存流用于输出图片

using (System.IO.MemoryStream ms = new System.IO.MemoryStream())

{

//图片格式指定为ＰＮＧ

image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

//清除缓冲区流中的所有输出

Response.ClearContent();

//输出流的ＨＴＴＰＭＩＭＥ类型设置为＂image/Png＂

Response.ContentType = "image/Png";

//输出图片的二进制流

Response.BinaryWrite(ms.ToArray());

}

}

finally

{

//释放 Ｂitmap 对象和 Ｇraphics 对象

g.Dispose();

image.Dispose();

}

}

}</FONT>

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.Drawing2D;



public partial class Default2 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

CreateCheckCodeImage(GenerateCheckCode());

}

/// <summary>

/// 生成随机校验码字符串

/// </summary>

/// <returns>生成的随机校验码字符串</returns>

public string GenerateCheckCode()

{

int number;

string strCode = string.Empty;

//随机数种子

Random radom = new Random();

for (int i = 0; i < 4; i++)

{

//随机的整数

number = radom.Next();

//字符从０－９，Ａ－Ｚ中随机产生，对应的ＡＳＣＩＩ码分别为48-57,65,90

number = number % 36;

if (number < 10)

{

number += 48;

}

else

{

number += 55;

}

strCode += ((char)number).ToString();

}

//在Cookie中保存校验码或Session中

Response.Cookies.Add(new HttpCookie("CheckCode", strCode));

return strCode;

}

/// <summary>

/// 根据校验码输出图片

/// </summary>

/// <param name="checkCode">产生的随机校验码</param>

public void CreateCheckCodeImage(string checkCode)

{

//若校验码为空，则直接返回

if (checkCode == null || checkCode.Trim() == string.Empty)

{


本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zhlu880516/archive/2008/07/12/2642473.aspx

[sxiaohui8709253]

session机制的问题吧 偶尔丢失很正常

[liss_2009]

没遇到过，帮顶！

[mngzilin]

无语，楼上贴那么多代码干嘛？说明白原因岂不是更好？

[wuyq11]

<img alt="" src="" style="cursor:pointer;" id="codeimg" onclick="this.src='validate.aspx?time=' + Math.random();" /> <script language="javascript" type="text/javascript">document.getElementById('codeimg').src = 'validate.aspx?time=' + Math.random(); </script>
session在页面记录

[mngzilin]

[Quote=引用 20 楼 wuyq11 的回复:]
……session在页面记录
[/Quote]
这才是重点

[supersyd]

IE6 下正常，在谷歌浏览器里，还是那个情况。。
我考虑到cookie不安全

[幻想多巴胺]

收了，呵呵

[supersyd]

晕了！结贴！开启了谷歌浏览器调试就有上述情况了！
大家谨记！！！！！！！！！！！！

[supersyd]

14楼的mngzilin
你的说法不成立。我用的vs2008，.net 3.5
好用

[moodboy1982]

mngzilin说话是对的，supersyd，你用VS2008也好还是VS2012也罢，这只是工具。机制没有改变。

[qiangwaer]

时间差问题