private async void refresh_Tapped(object sender, TappedRoutedEventArgs e)
{
httpclient.CancelPendingRequests();
string url = "http://gensav.altervista.org/";
var source = await httpclient.GetStringAsync(url); //PROBLEM
source = WebUtility.HtmlDecode(source);
HtmlDocument result = new HtmlDocument();
result.LoadHtml(source);
List<HtmlNode> toftitle = result.DocumentNode.Descendants().Where
(x => (x.Attributes["style"] != null
&& x.Attributes["style"].Value.Contains("font-size:14px;line-height:20px;margin-bottom:10px;"))).ToList();
var li = toftitle[0].InnerHtml.Replace("<br>", "\n");
li = li.Replace("<span style=\"text-transform: uppercase\">", "");
li = li.Replace("</span>", "");
postTextBlock.Text = li;
}
这段代码的作用基本上是从网站中检索一个字符串(HTML源代码,之后会被解析)。每当我点击一个按钮时执行此代码:第一次单击它它可以正常工作,但第二次我认为该方法(GetStringAsync)返回一个未完成的任务,然后使用 source <的旧值继续执行/ strong>即可。实际上,我的TextBlock不会更新。
任何解决方案?
答案 0 :(得分:2)
你可能得到一个缓存的回复。
愿这对您有用:
httpclient.CancelPendingRequests();
// disable caching
httpclient.DefaultRequestHeaders.Add("Cache-Control", "no-cache");
string url = "http://gensav.altervista.org/";
var source = await httpclient.GetStringAsync(url);
...
您还可以在网址中添加无意义的值,如下所示:
string url = "http://gensav.altervista.org/" + "?nocahce=" + Guid.NewGuid();
答案 1 :(得分:0)
为了防止Http响应被缓存,我这样做(在WP8.1中):
HttpBaseProtocolFilter filter = new HttpBaseProtocolFilter();
filter.CacheControl.ReadBehavior =
Windows.Web.Http.Filters.HttpCacheReadBehavior.MostRecent;
filter.CacheControl.WriteBehavior =
Windows.Web.Http.Filters.HttpCacheWriteBehavior.NoCache;
_httpClient = new HttpClient(filter);
以这种方式初始化您的HttpClient以防止缓存行为。