下面浅析通过提琴手行动code，我意识到，使用并行扩展我能够在最大2出站请求得到：

Analysing the code below in action through Fiddler, I realized that using Parallel Extensions I can get at maximum 2 outbound requests:

new string[] 
    {
        "http://stackoverflow.com",
        "http://superuser.com",
        "http://serverfault.com",
        "http://stackexchange.com"
    }
    .AsParallel()
    .Select(a => HttpWebRequest.Create(a).GetResponse())
    .ToArray()
    ;

我应该使用什么方法来最大限度地提高出站请求的数量？

What method should I use to maximize the number of outbound requests?

推荐答案

这code根据Wireshark的并行运行了我的机器上的所有6 HTTP请求：

This code runs all 6 HTTP requests in parallel on my machine according to Wireshark:

var urls = new string[] 
{
    "http://stackoverflow.com", 
    "http://superuser.com", 
    "http://serverfault.com",
    "http://stackexchange.com",
    "http://www.howtogeek.com",
    "http://meta.stackoverflow.com" 
};

var reqs = urls.Select<string, WebRequest>(HttpWebRequest.Create).ToArray();
var iars = reqs.Select(req => req.BeginGetResponse(null, null)).ToArray();
var rsps = reqs.Select((req, i) => req.EndGetResponse(iars[i])).ToArray();

基本上，它会创建一个的WebRequest 每个网址，电话 BeginGetResponse 每个然后调用 EndGetResponse 每个与的IAsyncResult 。

Basically it creates a WebRequest for each URL, calls BeginGetResponse on each and then calls EndGetResponse for each with the IAsyncResult.

该文档指出 BeginGetResponse 使用的托管线程池使HTTP请求。​​

The documentation states that BeginGetResponse uses The Managed Thread Pool to make the HTTP request.