急请高人指教：C#设置WebProxy后发送HttpWebRequest，HttpWebResponse为何超时？
急切请教大家一个问题！对您的任何建议表示感谢！！

我有一段程序是向服务端发送http request并接收response，一切正常，后来由于网络环境需要，要求设置http代理（通过IE设置http代理），为了支持http代理，我为代码设置了WebProxy属性（下面代码中被注释的那三句），可结果是：接收response总是超时（HttpWebResponse response = (HttpWebResponse)request.GetResponse();），急请高人指教！

代码片段如下：

try
{
Encoding encoding = Encoding.UTF8;
byte[] bytes = encoding.GetBytes(requestBody);

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(global.Hosts.SmapUri);
request.Method = "POST ";
request.ContentType = "application/x-www-form-urlencoded ";
request.ContentLength = bytes.Length;

//WebProxy proxyObject = new WebProxy( "192.168.1.112 ", 8080);
//request.Proxy = proxyObject;
//request.Proxy = WebProxy.GetDefaultProxy();

Stream sw = request.GetRequestStream();
sw.Write(bytes, 0, bytes.Length);
sw.Close();

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader readStream = new StreamReader(response.GetResponseStream(), encoding);
String responseBody = readStream.ReadToEnd();
response.Close();
readStream.Close();

}
catch (System.Exception e)
{
log.Info( "Exception: " + e.Message);
}


[解决办法]
if (proxy != null)
{
request.Proxy = proxy;
}

设好代理　应就行了，我一直这样用的.　注意看http代理是否可用.　
到网上搜一些可用的，来测试.　我有时，用QQ的代理功能.来测试代理是否可用.