爲了測試它,我使用combobox_selectionChanged事件來激活此功能,當selectedItem = 0顯示世界標題時,selectedItem = 1顯示體育標題,selectedItem = 2將可見性更改爲摺疊。當您選擇item0或更改ITEM1它可以工作,但一旦我改變ITEM2,它讓我system.StackOverflowExceptionUWP System.StackOverflowException
這裏是我的代碼`
CancellationTokenSource cts = null;
public async void NewsRepeat()
{
cts?.Cancel();
try
{
var localCts = cts = new CancellationTokenSource();
localCts.Token.ThrowIfCancellationRequested();
if (newsTpye.SelectedIndex == 0)
{
NewsPanel.Visibility = Visibility.Visible;
RootObject2 myNews = await NewsProxy.GetNews();
newsChannel.Text = "World Headlines";
for (k = 0; k <= 8; k++)
{
if (myNews.articles[k].title != null)
showTitle.Text = myNews.articles[k].title;
else
showTitle.Text = "";
if (myNews.articles[k].urlToImage != null)
newsImage.Source = new BitmapImage(new Uri(myNews.articles[k].urlToImage, UriKind.Absolute));
else
newsImage.Source = new BitmapImage(new Uri("ms-appx:///Assets/image/NoPic.jpg", UriKind.RelativeOrAbsolute));
if (myNews.articles[k].publishedAt != null)
showTime.Text = myNews.articles[k].publishedAt;
else
showTime.Text = "";
showDescription.Text = "(" + myNews.source + "): " + myNews.articles[k].description;
await Task.Delay(5000);
localCts.Token.ThrowIfCancellationRequested();
}
}
else if (newsTpye.SelectedIndex == 1)
{
NewsPanel.Visibility = Visibility.Visible;
RootObject3 mySportNews = await sportsNewsProxy.GetSportNews();
newsChannel.Text = "Sports Headlines";
for (k = 0; k <= 8; k++)
{
if (mySportNews.articles[k].title != null)
showTitle.Text = mySportNews.articles[k].title;
else
showTitle.Text = "";
if (mySportNews.articles[k].urlToImage != null)
newsImage.Source = new BitmapImage(new Uri(mySportNews.articles[k].urlToImage, UriKind.Absolute));
else
newsImage.Source = new BitmapImage(new Uri("ms-appx:///Assets/image/NoPic.jpg", UriKind.RelativeOrAbsolute));
if (mySportNews.articles[k].publishedAt != null)
showTime.Text = mySportNews.articles[k].publishedAt;
else
showTime.Text = "";
showDescription.Text = "(" + mySportNews.source + "): " + mySportNews.articles[k].description;
await Task.Delay(5000);
localCts.Token.ThrowIfCancellationRequested();
}
}
else if (newsTpye.SelectedIndex == 2)
{
NewsPanel.Visibility = Visibility.Collapsed;
}
NewsRepeat();
}
catch (OperationCanceledException)
{
// Swallow this exception only - this is probably
// the one we've thrown ourselves
}
}
private void newsType_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
NewsRepeat();
}`
如何以及何時退出您的'NewsRepeat()'方法?我想知道爲什麼在其他兩種情況下沒有StackOverflow。 –
@ ravi kumar其實從來沒有,我只是簡單地隱藏這個面板,你可以教如何退出? – WANGJAY