WebClient 类中的 Headers 集合有一个非常奇怪的问题。
这是我的例子:
WebClient client = new WebClient();
client.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0");
client.Headers.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
client.Headers.Add("Accept-Language", "pl,en-us;q=0.7,en;q=0.3");
Console.WriteLine("Before request:");
foreach (string key in client.Headers)
{
Console.WriteLine(key + ": " + client.Headers[key]);
}
client.DownloadString("http://www.google.com");
Console.WriteLine();
Console.WriteLine("After request:");
foreach (string key in client.Headers)
{
Console.WriteLine(key + ": " + client.Headers[key]);
}
Console.ReadLine();
我运行这个简单程序的结果:
Before request:
User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: pl,en-us;q=0.7,en;q=0.3
After request:
Accept-Language: pl,en-us;q=0.7,en;q=0.3
为什么我的标题消失了?