C# - 定期刷新方法

Question

I want to refresh my UWP-UI periodically after like 5 minutes. I have a Method "Page_Loaded" where all information from the classes is sent to the UI-Elements. So if i refresh this method, the UI would do too, right?

The Code is like this:

private async void Page_Loaded(object sender, RoutedEventArgs e)
        {
            RootObject myWeather = await Openweathermap.GetWeather();
            string icon = String.Format("http://openweathermap.org/img/wn/{0}@2x.png", myWeather.weather[0].icon);
            ResultImage.Source = new BitmapImage(new Uri(icon, UriKind.Absolute));

            TempTextBlock.Text = ((int)myWeather.main.temp).ToString() + "°";
            DescriptionTextBlock.Text = myWeather.weather[0].description;
            LocationTextBlock.Text = myWeather.name;

            var articlesList = NewsAPI.GetNews().Result.articles;
            lvNews.ItemsSource = articlesList;

            Welcometxt.Text = MainPage.WelcomeText();
        }

So, how do I refresh this method after 5 Minutes, so that it gets the new information and sends it to the UI?

Answer 1

So, how do I refresh this method after 5 Minutes, so that it gets the new information and sends it to the UI?

Repeatedly calling the Page_Loaded method is not a recommended practice, the recommended approach is to use DispatcherTimer , a timer within the UI thread.

We can extract the code inside Page_Loaded as a function.

private DispatcherTimer _timer;
public MainPage()
{
    this.InitializeComponent();
    _timer = new DispatcherTimer();
    _timer.Interval = TimeSpan.FromMinutes(5);
    _timer.Tick += Timer_Tick;
}

private async Task GetData()
{
    RootObject myWeather = await Openweathermap.GetWeather();
    string icon = String.Format("http://openweathermap.org/img/wn/{0}@2x.png", myWeather.weather[0].icon);
    ResultImage.Source = new BitmapImage(new Uri(icon, UriKind.Absolute));

    TempTextBlock.Text = ((int)myWeather.main.temp).ToString() + "°";
    DescriptionTextBlock.Text = myWeather.weather[0].description;
    LocationTextBlock.Text = myWeather.name;

    var articlesList = NewsAPI.GetNews().Result.articles;
    lvNews.ItemsSource = articlesList;

    Welcometxt.Text = MainPage.WelcomeText();
}

private async void Timer_Tick(object sender, object e)
{
    await GetData();
}

private async void Page_Loaded(object sender, RoutedEventArgs e)
{
    await GetData();
    _timer.Start();
}

protected override void OnNavigatedFrom(NavigationEventArgs e)
{
    _timer.Stop();
    base.OnNavigatedFrom(e);
}

With DispatcherTimer.Tick , we can execute tasks regularly, and when we leave the page, we can stop the timer.