用WPF/mvvmlighttoolkit处理窗口关闭事件

我只需在视图构造函数中关联处理程序:

MyWindow() 
{
    // Set up ViewModel, assign to DataContext etc.
    Closing += viewModel.OnWindowClosing;
}

然后将处理程序添加到 ViewModel :

using System.ComponentModel;

public void OnWindowClosing(object sender, CancelEventArgs e) 
{
   // Handle closing logic, set e.Cancel as needed
}

在本例中,通过使用更复杂的模式和更间接的方式(额外的5行xamlplus),您只获得了复杂性 Command 模式)。

. 即使事件绑定在视图后面的代码中 不依赖于视图和结束逻辑 可以进行单元测试 .

这个代码很好用:

视图模型.cs:

public ICommand WindowClosing
{
    get
    {
        return new RelayCommand<CancelEventArgs>(
            (args) =>{
                     });
    }
}

<i:Interaction.Triggers>
    <i:EventTrigger EventName="Closing">
        <command:EventToCommand Command="{Binding WindowClosing}" PassEventArgsToCommand="True" />
    </i:EventTrigger>
</i:Interaction.Triggers>

假设:

• ViewModel被指定给 DataContext
• xmlns:command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.SL5"
• xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

这个选项更容易,也许适合你。在视图模型构造函数中,可以订阅主窗口关闭事件,如下所示:

Application.Current.MainWindow.Closing += new CancelEventHandler(MainWindow_Closing);

void MainWindow_Closing(object sender, CancelEventArgs e)
{
            //Your code to handle the event
}

祝你一切顺利。

如果您不想知道ViewModel中的窗口(或它的任何事件),这里有一个根据MVVM模式的答案。

public interface IClosing
{
    /// <summary>
    /// Executes when window is closing
    /// </summary>
    /// <returns>Whether the windows should be closed by the caller</returns>
    bool OnClosing();
}

在ViewModel中添加接口和实现

public bool OnClosing()
{
    bool close = true;

    //Ask whether to save changes och cancel etc
    //close = false; //If you want to cancel close

    return close;
}

在窗口中我添加了结束事件。这种代码隐藏不会破坏MVVM模式。视图可以知道viewmodel!

void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
    IClosing context = DataContext as IClosing;
    if (context != null)
    {
        e.Cancel = !context.OnClosing();
    }
}

PassEventArgsToCommand=“真” 是 需要如上所述。

(归功于Laurent Bugnion http://blog.galasoft.ch/archive/2009/10/18/clean-shutdown-in-silverlight-and-wpf-applications.aspx )

   ... MainWindow Xaml
   ...
   WindowStyle="ThreeDBorderWindow" 
    WindowStartupLocation="Manual">



<i:Interaction.Triggers>
    <i:EventTrigger EventName="Closing">
        <cmd:EventToCommand Command="{Binding WindowClosingCommand}" PassEventArgsToCommand="True" />
    </i:EventTrigger>
</i:Interaction.Triggers> 

在视图模型中:

///<summary>
///  public RelayCommand<CancelEventArgs> WindowClosingCommand
///</summary>
public RelayCommand<CancelEventArgs> WindowClosingCommand { get; private set; }
 ...
 ...
 ...
        // Window Closing
        WindowClosingCommand = new RelayCommand<CancelEventArgs>((args) =>
                                                                      {
                                                                          ShutdownService.MainWindowClosing(args);
                                                                      },
                                                                      (args) => CanShutdown);

在停机服务中

    /// <summary>
    ///   ask the application to shutdown
    /// </summary>
    public static void MainWindowClosing(CancelEventArgs e)
    {
        e.Cancel = true;  /// CANCEL THE CLOSE - let the shutdown service decide what to do with the shutdown request
        RequestShutdown();
    }

RequestShutdown看起来像下面这样,但是basicallyRequestShutdown或它的名称决定了是否关闭应用程序(这将愉快地关闭窗口):

...
...
...
    /// <summary>
    ///   ask the application to shutdown
    /// </summary>
    public static void RequestShutdown()
    {

        // Unless one of the listeners aborted the shutdown, we proceed.  If they abort the shutdown, they are responsible for restarting it too.

        var shouldAbortShutdown = false;
        Logger.InfoFormat("Application starting shutdown at {0}...", DateTime.Now);
        var msg = new NotificationMessageAction<bool>(
            Notifications.ConfirmShutdown,
            shouldAbort => shouldAbortShutdown |= shouldAbort);

        // recipients should answer either true or false with msg.execute(true) etc.

        Messenger.Default.Send(msg, Notifications.ConfirmShutdown);

        if (!shouldAbortShutdown)
        {
            // This time it is for real
            Messenger.Default.Send(new NotificationMessage(Notifications.NotifyShutdown),
                                   Notifications.NotifyShutdown);
            Logger.InfoFormat("Application has shutdown at {0}", DateTime.Now);
            Application.Current.Shutdown();
        }
        else
            Logger.InfoFormat("Application shutdown aborted at {0}", DateTime.Now);
    }
    }

在窗口或usercontrol等顶部的定义中,定义命名空间:

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

就在这个定义之下:

<i:Interaction.Triggers>
        <i:EventTrigger EventName="Closing">
            <i:InvokeCommandAction Command="{Binding WindowClosing}" CommandParameter="{Binding}" />
        </i:EventTrigger>
</i:Interaction.Triggers>

public ICommand WindowClosing { get; private set; }

在viewmodel构造函数中附加delegatecommand:

this.WindowClosing = new DelegateCommand<object>(this.OnWindowClosing);

最后,在关闭控件/窗口/任何东西时要访问的代码:

private void OnWindowClosing(object obj)
        {
            //put code here
        }

我很想在您的应用程序.xaml.cs允许您决定是否关闭应用程序的文件。

例如,您可以在应用程序.xaml.cs文件:

protected override void OnStartup(StartupEventArgs e)
{
    base.OnStartup(e);
    // Create the ViewModel to attach the window to
    MainWindow window = new MainWindow();
    var viewModel = new MainWindowViewModel();

    // Create the handler that will allow the window to close when the viewModel asks.
    EventHandler handler = null;
    handler = delegate
    {
        //***Code here to decide on closing the application****
        //***returns resultClose which is true if we want to close***
        if(resultClose == true)
        {
            viewModel.RequestClose -= handler;
            window.Close();
        }
    }
    viewModel.RequestClose += handler;

    window.DataContaxt = viewModel;

    window.Show();

}

然后在主WindowViewModel代码中,可以有以下内容:

#region Fields
RelayCommand closeCommand;
#endregion

#region CloseCommand
/// <summary>
/// Returns the command that, when invoked, attempts
/// to remove this workspace from the user interface.
/// </summary>
public ICommand CloseCommand
{
    get
    {
        if (closeCommand == null)
            closeCommand = new RelayCommand(param => this.OnRequestClose());

        return closeCommand;
    }
}
#endregion // CloseCommand

#region RequestClose [event]

/// <summary>
/// Raised when this workspace should be removed from the UI.
/// </summary>
public event EventHandler RequestClose;

/// <summary>
/// If requested to close and a RequestClose delegate has been set then call it.
/// </summary>
void OnRequestClose()
{
    EventHandler handler = this.RequestClose;
    if (handler != null)
    {
        handler(this, EventArgs.Empty);
    }
}

#endregion // RequestClose [event]

基本上,窗口事件不能分配给MVVM。一般情况下,关闭按钮会显示一个对话框,询问用户“保存:是/否/取消”,这可能是MVVM无法实现的。

因此,如果CanExecute()调用为true,或者在OnClosed事件中,调用模型.关闭.执行()

我没有做过很多测试,但它似乎起作用了。我想到的是:

namespace OrtzIRC.WPF
{
    using System;
    using System.Windows;
    using OrtzIRC.WPF.ViewModels;

    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        private MainViewModel viewModel = new MainViewModel();
        private MainWindow window = new MainWindow();

        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);

            viewModel.RequestClose += ViewModelRequestClose;

            window.DataContext = viewModel;
            window.Closing += Window_Closing;
            window.Show();
        }

        private void ViewModelRequestClose(object sender, EventArgs e)
        {
            viewModel.RequestClose -= ViewModelRequestClose;
            window.Close();
        }

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            window.Closing -= Window_Closing;
            viewModel.RequestClose -= ViewModelRequestClose; //Otherwise Close gets called again
            viewModel.CloseCommand.Execute(null);
        }
    }
}

为此,我们使用attachedCommand行为。您可以将任何事件附加到视图模型上的命令,以避免任何代码隐藏。

我们在整个解决方案中都使用它,几乎没有代码隐藏

http://marlongrech.wordpress.com/2008/12/13/attachedcommandbehavior-v2-aka-acb/

出口 视图模型中的命令:

ICommand _exitCommand;
public ICommand ExitCommand
{
    get
    {
        if (_exitCommand == null)
            _exitCommand = new RelayCommand<object>(call => OnExit());
        return _exitCommand;
    }
}

void OnExit()
{
     var msg = new NotificationMessageAction<object>(this, "ExitApplication", (o) =>{});
     Messenger.Default.Send(msg);
}

Messenger.Default.Register<NotificationMessageAction<object>>(this, (m) => if (m.Notification == "ExitApplication")
{
     Application.Current.Shutdown();
});

另一方面,我处理 Closing MainWindow ,使用ViewModel的实例:

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{ 
    if (((ViewModel.MainViewModel)DataContext).CancelBeforeClose())
        e.Cancel = true;
}

CancelBeforeClose 检查视图模型的当前状态,如果应停止关闭,则返回true。

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        MessageBox.Show("closing");
    }