c# - 如何在 Windows Phone 上异步加载数据

Question

我正在尝试异步加载数据，但第一次没有显示进度条，就像 UI 线程忙于调用 BackgroundWork 并且不呈现控件一样。我做错了什么？

这是异步代码，灵感来自这个问题windows phone 7 progress bar for a listbox loading data

private void Embarques_Loaded(object sender, RoutedEventArgs e)
{

    progressBar.Visibility = System.Windows.Visibility.Visible;

    BackgroundWorker bw = new BackgroundWorker();

    bw.RunWorkerCompleted += (s, ea) =>
        Deployment.Current.Dispatcher.BeginInvoke(() =>
        {
            progressBar.Visibility = System.Windows.Visibility.Collapsed;
            txtUltimaAtualizacao.Text = DateTime.Now.ToString();
        });

    bw.DoWork += (s, ea) =>
        Deployment.Current.Dispatcher.BeginInvoke(CarregaItens);

    bw.RunWorkerAsync();
}

Answer 1

假设CarregaItens()是你的加载过程，你不应该调用Deployment.Current.Dispatcher.BeginInvoke它，因为它只是将它从后台线程提升到 UI 线程，从而在它运行时冻结你的应用程序。只需致电：

bw.DoWork += (s, ea) => CarregaItens();