如何在Windows Phone上刷新HttpWebRequest对象

Question

I'm writing a windows phone application where I need to do a http request. This request return to me a random value it changes always when I request its url.

So I have a app with a button when I click it I receive the random value that I want, but, if I click the button again I receive the same random value!! I put a breakpoint on the server side and it is reached just once, if a click the button 10 times it will reach the breakpoint just the first time!! I need whenever I click the button I have a new random value!

And I need to use a CookieContainer because on my server I need to keep some objects defined in this session. If I dont use CookieContainer I cant keep the session, so when I call the second request I haven't no objects there.

private async Task<string> requestURLData(HttpWebRequest request)
{

HttpWebResponse response = (HttpWebResponse) await Task<WebResponse>.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, request);

var responseStream = response.GetResponseStream();
var sr = new StreamReader(responseStream);

string received = await sr.ReadToEndAsync();

return received;
}


private async Task<string> requestUrl(string url, CookieContainer cookie)
{
var request = WebRequest.Create(new Uri(url)) as HttpWebRequest;
request.CookieContainer = cookie;

return await this.requestURLData(request);

}


private async Button_Click(object sender, RoutedEventArgs e)
{

CookieContainer cookie = new CookieContainer();
var result = await this.requestUrl(this.urlBase + "getRandomNum", cookie);

result = await this.requestUrl(this.urlBase + "getAnotherValue", cookie);

}

Answer 1

You're running into response caching - append a random string to the end of your url that your server ignores to guarantee that you don't hit the cache:

Random _rand = new Random();

private async Button_Click(object sender, RoutedEventArgs e)
{

   CookieContainer cookie = new CookieContainer();
   var result = await this.requestUrl(this.urlBase + "getRandomNum&rubbish=" + _rand.Next(), cookie);
   ...
}