郁闷呀~~为什么HttpWebRequest下载一个图形验证码会无效

[dreamw]

Expires: -1
图片验证码里面有这个参数的

我的源程序如下:

private void ycadDownload(string imgUrl) //下载图形验证码
{
byte[] bytes = new byte[512];
int readfile;
string localPicUrl = Environment.CurrentDirectory.ToString() + "\\ycad\\" + DateTime.Now.ToString("yyyyMMddhhmmss") + stac._163_bmp;
FileStream fs = new FileStream(localPicUrl, FileMode.Create);
try
{
string cog_certfile = Environment.CurrentDirectory.ToString() + "\\certfile\\aa.cer";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(imgUrl);
request.ContentType = "image/png";
request.KeepAlive = false;
request.UserAgent = @"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; .NET CLR 2.0.50727)";
request.Method = "GET";
request.CookieContainer = stac.PicContainer;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
response.Cookies = stac.PicContainer.GetCookies(request.RequestUri);
Stream myRequestStream = request.GetResponse().GetResponseStream();
readfile = myRequestStream.Read(bytes, 0, 512);

fs.Write(bytes, 0, readfile);
readfile = myRequestStream.Read(bytes, 0, 512);


fs.Close();
myRequestStream.Close();
response.Close();

}
catch (Exception er)
{
MessageBox.Show(er.Message);
fs.Close();
}


}

[dreamw]

回laodeng72586(一直在走，却为何是原地踏步)

==========
我想也有这个可能,请教有什么解决的办法吗?
这段代码我用到其它是可以用得上的哦.

[dreamw]

郁闷,顶

[dreamw2]

我又自顶,唉..没多少发啦,大侠帮帮忙,给点思路也好呀

[dreamw]

把图片验证码下载了,但POST提交的时候,说是验证码错误??怎么回事呀??

[dreamw]

看到孟老大啦,,孟老大快来帮我看看~~

[孟子E章]

发送到时候将Cookie一并发送

[laodeng72586]

从别的网站保存验证码，后提交？
我想可能是别人使用Session保存验证码的值，你下载的和提交时被看作两次新的访问了，所以前后的Session验证码也就不一样了。

[dreamw]

request.CookieContainer = stac.PicContainer;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
response.Cookies = stac.PicContainer.GetCookies(request.RequestUri);

这个语句有呀.

这个代码用到其它验证码上是可以的,就是带有这个参数的Expires: -1 的不行

[dreamw]

郁闷,顶

[dreamw]

郁闷,顶

[dreamw]

郁闷,顶