我需要使用 C# 和 XAML 在 Windows 8 Metro 应用程序中激活启动画面并向其添加进度环。我添加了扩展的启动画面，但它根本没有显示！谁能告诉我该怎么做？
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using SplashScreenSample;
// The Blank Application template is documented at http://go.microsoft.com/fwlink/? LinkId=234227
namespace App1
{
/// <summary>
/// Provides application-specific behavior to supplement the default Application class.
/// </summary>
sealed partial class App : Application
{
/// <summary>
/// Initializes the singleton application object. This is the first line of authored code
/// executed, and as such is the logical equivalent of main() or WinMain().
/// </summary>
public App()
{
this.InitializeComponent();
this.Suspending += OnSuspending;
}
/// <summary>
/// Invoked when the application is launched normally by the end user. Other entry points
/// will be used when the application is launched to open a specific file, to display
/// search results, and so forth.
/// </summary>
/// <param name="args">Details about the launch request and process.</param>
protected override void OnLaunched(LaunchActivatedEventArgs args)
{
// Do not repeat app initialization when already running, just ensure that
// the window is active
/* if (args.PreviousExecutionState != ApplicationExecutionState.Running)
{
bool loadState = (args.PreviousExecutionState == ApplicationExecutionState.Terminated);
ExtendedSplash extendedSplash = new ExtendedSplash(args.SplashScreen, loadState);
Window.Current.Content = extendedSplash;
}
Window.Current.Activate();*/
if (args.PreviousExecutionState == ApplicationExecutionState.Running)
{
Window.Current.Activate();
return;
}
if (args.PreviousExecutionState == ApplicationExecutionState.Terminated)
{
//TODO: Load state from previously suspended application
}
// Create a Frame to act navigation context and navigate to the first page
var rootFrame = new Frame();
rootFrame.Navigate(typeof(MainPage));
// Place the frame in the current window and ensure that it is active
Window.Current.Content = rootFrame;
Window.Current.Activate();
if (!rootFrame.Navigate(typeof(MainPage)))
{
throw new Exception("Failed to create initial page");
}
// Place the frame in the current Window and ensure that it is active
Window.Current.Content = rootFrame;
Window.Current.Activate();
}
/// <summary>
/// Invoked when application execution is being suspended. Application state is saved
/// without knowing whether the application will be terminated or resumed with the contents
/// of memory still intact.
/// </summary>
/// <param name="sender">The source of the suspend request.</param>
/// <param name="e">Details about the suspend request.</param>
private void OnSuspending(object sender, SuspendingEventArgs e)
{
var deferral = e.SuspendingOperation.GetDeferral();
//TODO: Save application state and stop any background activity
deferral.Complete();
}
/// <summary>
/// Invoked when the application is activated to display search results.
/// </summary>
/// <param name="args">Details about the activation request.</param>
protected override void OnSearchActivated(Windows.ApplicationModel.Activation.SearchActivatedEventArgs args)
{
App1.SearchResultsPage1.Activate(args.QueryText, args.PreviousExecutionState);
}
}
}