我有一个WPF项目,由项目向导添加了一个启动屏幕。在同一个启动屏幕中,我想添加一个进度条样式的计量器。有人知道如何实现吗?
我有一个WPF项目,由项目向导添加了一个启动屏幕。在同一个启动屏幕中,我想添加一个进度条样式的计量器。有人知道如何实现吗?
这是我的方案。我之所以这样做的动机是,我不想让初始化代码在UI线程上运行,并且通常我希望将初始化代码放在我的App类中(而不是启动屏幕)。
基本上,我将应用程序的StartupUri
设置为我的启动屏幕,从而开始推动进程。
在启动屏幕上,我调用委托返回到应用程序。这在一个工作线程上运行。在启动屏幕上,我处理EndInvoke
并关闭窗口。
在应用程序初始化委托中,我完成工作,并在最后创建和打开正常的主窗口。在工作负载期间,我还有一个在Splash上允许更新进度的方法。
好的,代码相当简短,不包括主窗口代码(对所有这些都没有影响),但它使用匿名委托来躲闪,因此请仔细阅读,最好在调试器中测试。
以下是代码....
<Application x:Class="SplashScreenDemo.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="Splash.xaml">
<Application.Resources>
</Application.Resources>
</Application>
应用程序代码后台...
internal delegate void Invoker();
public partial class App : Application
{
public App()
{
ApplicationInitialize = _applicationInitialize;
}
public static new App Current
{
get { return Application.Current as App; }
}
internal delegate void ApplicationInitializeDelegate(Splash splashWindow);
internal ApplicationInitializeDelegate ApplicationInitialize;
private void _applicationInitialize(Splash splashWindow)
{
// fake workload, but with progress updates.
Thread.Sleep(500);
splashWindow.SetProgress(0.2);
Thread.Sleep(500);
splashWindow.SetProgress(0.4);
Thread.Sleep(500);
splashWindow.SetProgress(0.6);
Thread.Sleep(500);
splashWindow.SetProgress(0.8);
Thread.Sleep(500);
splashWindow.SetProgress(1);
// Create the main window, but on the UI thread.
Dispatcher.BeginInvoke(DispatcherPriority.Normal, (Invoker)delegate
{
MainWindow = new Window1();
MainWindow.Show();
});
}
}
闪屏xaml
(实际上,这里没有太有趣的东西...)
<Window x:Class="SplashScreenDemo.Splash"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Splash" Height="300" Width="300">
<Grid>
<TextBlock Height="21" Margin="91,61,108,0" VerticalAlignment="Top">Splash Screen</TextBlock>
<ProgressBar Name="progBar" Margin="22,122,16,109" Minimum="0" Maximum="1"/>
</Grid>
</Window>
闪屏代码后端...
public partial class Splash : Window
{
public Splash()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Splash_Loaded);
}
void Splash_Loaded(object sender, RoutedEventArgs e)
{
IAsyncResult result = null;
// This is an anonymous delegate that will be called when the initialization has COMPLETED
AsyncCallback initCompleted = delegate(IAsyncResult ar)
{
App.Current.ApplicationInitialize.EndInvoke(result);
// Ensure we call close on the UI Thread.
Dispatcher.BeginInvoke(DispatcherPriority.Normal, (Invoker)delegate { Close(); });
};
// This starts the initialization process on the Application
result = App.Current.ApplicationInitialize.BeginInvoke(this, initCompleted, null);
}
public void SetProgress(double progress)
{
// Ensure we update on the UI Thread.
Dispatcher.BeginInvoke(DispatcherPriority.Normal, (Invoker)delegate { progBar.Value = progress; });
}
}
由于工作是在工作线程上完成的,进度条将会很好地更新,并且您在启动画面上拥有的任何动画都将保持娱乐性。
Ali的答案在.NET Core上不起作用。然而,有一个解决方法,我认为更加直接。我相信它适用于所有“最近”的.NET版本(可能自Task.Run被添加以来)。
我使用了类似的方法,使用另一个窗口作为启动画面。
我的App.xaml使用Startup事件而不是StartupUri。我相信这没有任何区别,但是。
<Application x:Class="SplashScreenDemo.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Startup="OnStartup">
<Application.Resources>
</Application.Resources>
</Application>
我不为初始化声明新的委托类型,而是直接使用一个方法。 创建和显示主窗口可能需要一些时间,因此我认为最好只在窗口加载完成时返回,通过调整其Loaded事件。我们使用EventWaitHandle来实现。
public partial class App : Application
{
public App()
{
}
public static new App Current { get => Application.Current as App; }
private void OnStartup(object sender, StartupEventArgs e)
{
var splashScreen = new SplashScreenDemo.Splash();
splashScreen.Show();
}
internal void InitializeApplication(Splash splashWindow)
{
// fake workload, but with progress updates.
Thread.Sleep(500);
splashWindow.SetProgress(0.25);
Thread.Sleep(500);
splashWindow.SetProgress(0.5);
Thread.Sleep(500);
splashWindow.SetProgress(0.75);
EventWaitHandle mainWindowLoaded = new ManualResetEvent(false);
// Create the main window, but on the UI thread.
Dispatcher.BeginInvoke((Action)(() =>
{
MainWindow = new Window1();
MainWindow.Loaded += (sender, e) =>
{
mainWindowLoaded.Set();
};
splashWindow.SetProgress(0.9);
MainWindow.Show();
splashWindow.SetProgress(1);
}));
// Wait until the Main window has finished initializing and loading
mainWindowLoaded.WaitOne();
}
}
启动画面窗口可以使用一些窗口属性:
<Window x:Class="SplashScreenDemo.Splash"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Splash" Height="300" Width="300" WindowStartupLocation="CenterScreen"
WindowStyle="None" ResizeMode="NoResize" Topmost="True">
<Grid>
<TextBlock Height="21" VerticalAlignment="Top" TextAlignment="Center" Text="Loading"/>
<ProgressBar Name="progBar" Margin="20,100" Minimum="0" Maximum="1"/>
</Grid>
</Window>
public partial class Splash : Window
{
public Splash()
{
InitializeComponent();
this.Loaded += Splash_Loaded;
}
private async void Splash_Loaded(object sender, RoutedEventArgs e)
{
await Task.Run(() =>
{
App.Current.InitializeApplication(this);
App.Current.Dispatcher.BeginInvoke((Action)(() =>
{
Close();
}));
});
}
public void SetProgress(double progress)
{
Dispatcher.BeginInvoke((Action)(() => progBar.Value = progress));
}
}
Application.OnExit()
被触发。所以我唯一成功让它工作的方法是:
Application.cs:
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
_mySplashScreenWindow.Show();
Task.Run(async () =>
{
for (var i = 1; i <= 20; i++)
{
_mySplashScreenWindow.Dispatcher.Invoke(() =>
{
_mySplashScreenWindow.SomeTextBlock.Text = i.ToString();
_mySplashScreenWindow.Progress = i; // or i / 20 for %
});
await Task.Delay(250);
}
})
.ContinueWith(_ =>
{
MainWindow = null;
var mainWindow = new MainWindow();
// Or if you have access to the SplashScreen in the MainWindow, you can subscribe there
mainWindow.Loaded += (sender, args) =>
{
_mySplashScreenWindow.Close();
_mySplashScreenWindow = null;
}
MainWindow = mainWindow;
mainWindow.ShowDialog();
}, TaskScheduler.FromCurrentSynchronizationContext());
}