[英]UI freezes for 1 or 2 sec using httprequest background worker
我的代码有什么问题? 后台工作程序是否未正确设置,导致UI冻结? 似乎延迟开始于调用BeginGetResponse时,然后从Web服务器返回结果后正常恢复。
private void updateProgressbar()
{
bgWorker = new BackgroundWorker();
bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
bgWorker.RunWorkerAsync();
}
private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
string path = "http://www.somestring.com/script.php?a=b");
Uri uriString = new Uri(path);
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uriString);
request.UserAgent = "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0)";
request.BeginGetResponse(new AsyncCallback(ReadCallback), request);
}
private void ReadCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
using (StreamReader streamReader1 = new StreamReader(response.GetResponseStream()))
{
string resultString = streamReader1.ReadToEnd();
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
JsonMainProgressbar progressBarValue;
progressBarValue = JsonConvert.DeserializeObject<JsonMainProgressbar>(resultString);
this.ProgressBar.Value = Convert.ToInt32(progressBarValue.userclicks / progressBarValue.countryclicks * 100);
this.txtContribution.Text = "your contribution: " + this.ProgressBar.Value + "%";
Debug.WriteLine("Progressbar updated");
});
}
}
我认为您对UI线程做了太多工作,而在后台线程上ReadCallback
却做得不够。 尝试在传递给BeginInvoke()
的lambda函数之外尽可能多地(*)移动。
(*),即安全无InvalidCrossThreadExceptions
或竞争条件...
在这种情况下,请尝试以下操作:
string resultString = streamReader1.ReadToEnd();
JsonMainProgressbar progressBarValue;
progressBarValue = JsonConvert.DeserializeObject<JsonMainProgressbar>(resultString);
int progressBarValueInt = Convert.ToInt32(progressBarValue.userclicks /
progressBarValue.countryclicks * 100);
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
this.ProgressBar.Value = progressBarValueInt;
this.txtContribution.Text = "your contribution: " + progressBarValueInt + "%";
Debug.WriteLine("Progressbar updated");
});
(假设您可以在后台线程中安全地使用JsonMainProgressBar
)
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