WebClient DownloadString 不返回任何内容

我想从海盗湾的搜索查询中获取源代码，我的代码中有这个，但它不返回任何内容：

WebClient webpage = new WebClient();
string source=  webpage.DownloadString("http://thepiratebay.sx/search/documentary/0/99/0");

这是一个快速测试：

xaml:

<Label Content="{Binding ElementName=window_name, Path=SourceTest}"></Label>
<Label Content="{Binding ElementName=window_name, Path=SourceTest2}"></Label>

Code:

string source_url = "http://thepiratebay.sx/search/documentary";

WebClient webpage = new WebClient();
SourceTest = webpage.DownloadString(source_url);
if (SourceTest == "")
SourceTest = "stream was empty.";


source_url = "http://www.google.com";

webpage = new WebClient();
SourceTest2 = webpage.DownloadString(source_url);
if (SourceTest2 == "")
    SourceTest2 = "stream was empty.";

您的网址将返回一个空字符串，另一边的 Google 将为您提供您正在寻找的来源。

Edit :正如我所假设的，您需要像网络浏览器一样进行识别。这适用于您的查询：

string source_url = "http://thepiratebay.sx/search/documentary/0/99/0";

using (var webpage = new WebClient())
{
    webpage.Headers[HttpRequestHeader.UserAgent] = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2";
    SourceTest = webpage.DownloadString(source_url);
}