如何在c# Windows应用程序中发送令牌到url

使用System.Net.WebClient和DownloadString, URL内容给我一个令牌。服务器使用这个令牌作为"https://address/page?token=AAABBBXXX"。通过使用以下代码

string contents;
string token;
string url = @"https://address/login";
var wc = new System.Net.WebClient();
contents = wc.DownloadString(url);
token = contents.Substring(contents.IndexOf("page.public.pageToken = '") + "page.public.pageToken = '".Length, 32);
url = "https://address/page?token=" + token;
**contents = wc.DownloadString(url);** //error error error !!!!

我可以从页面内容获得令牌值，但如何发送此令牌并验证我的请求?最后一行导致服务器错误超时!我应该在任何会话中保存令牌值吗?如何在Windows应用程序?

using(WebClient wc = new WebClient()
{
    string WebURL = @"http://www.mywebsite.com/somefolder/somepage";
    NameValueCollection param = new NameValueCollection()
    {
        { "token", "abcdefghijklmnopqrstuvwxyz01234567890" }
    };
    object WebResponse = Encoding.UTF8.GetString(wc.UploadValues(WebURL, "GET", param));
}