窗口加载和WPF [英] Window Loaded and WPF

问题描述

我在Windows 2012中有一个WPF项目，我需要在Window Loaded事件中加载一些信息。我需要在View Model中执行此操作，而不是在CodeBehind中执行此操作。我试图使用以下代码：

在我的xaml：

 <交互：Interaction.Behaviors> 
<行为：WindowLoadedBehavior LoadedCommand ={Binding WindowLoadedCommand}/> 
< / interactivity：Interaction.Behaviors> 
  

在我的查看模型中：

  private DelegateCommand _WindowLoadedCommand; 
 
 public DelegateCommand WindowLoadedCommand 
 {
 get 
 {
 return _WindowLoadedCommand; 
} 
 private set 
 {
 _WindowLoadedCommand = value; 
} 
} 
 
 public ShellViewModel（）
 {
 WindowLoadedCommand = new DelegateCommand（WindowLoadedAction）; 
} 
 
 protected void WindowLoadedAction（）
 {
 ... 
} 
  

我附加的行为：

  public class WindowLoadedBehavior：Behavior< FrameworkElement> 
 {
 [SuppressMessage（Microsoft.StyleCop.CSharp.MaintainabilityRules，SA1401：FieldsMustBePrivate，Justification =Dependency Property。Allow public）] 
 public static DependencyProperty LoadedCommandProperty = DependencyProperty 。注册（LoadedCommand，typeof（ICommand），typeof（WindowLoadedBehavior），新的PropertyMetadata（null））; 
 
 public ICommand LoadedCommand 
 {
 get {return（ICommand）GetValue（LoadedCommandProperty）; } 
 set {SetValue（LoadedCommandProperty，value）; 
} 
 
 protected override void OnAttached（）
 {
 base.OnAttached（）; 
 
 AssociatedObject.Loaded + = AssociatedObject_Loaded; 
} 
 
 protected override void OnDetaching（）
 {
 AssociatedObject.Loaded  -  = AssociatedObject_Loaded; 
 
 base.OnDetaching（）; 
 
 
 private void AssociatedObject_Loaded（object sender，RoutedEventArgs e）
 {
 if（LoadedCommand！= null）
 LoadedCommand.Execute（null）; 
} 
} 
  

OnAttached，AssociatedObject_Loaded和LoadedCommand get都被触发，但是LoadedCommand集没有触发，并且显然WindowLoadedCommand没有触发。任何线索我可以做些什么来使这项工作？

解决方案

有几个选择。他们中的几个列在这里：

如何在WPF MVVM中调用窗口的加载事件？

然而，在机会中你或任何其他人都在乎你花了几个小时来完成一个应该花了30秒的任务，你可能要试试这个。

  public MainWindow（）
 {
 InitializeComponent（）; 
 
 this.Loaded + = new RoutedEventHandler（MainWindow_Loaded）; 
} 
 
 void MainWindow_Loaded（object sender，RoutedEventArgs e）
 {
 ShellViewModel.Instance.WindowLoadedCommand.Execute（null）; 
} 
  

I have a WPF project in Windows 2012 in which I need to load some information in the Window Loaded event. I need to do this in the View Model rather than in the CodeBehind, though. I am attempting to use the following code:

In my xaml:

<interactivity:Interaction.Behaviors>
    <behaviors:WindowLoadedBehavior LoadedCommand="{Binding WindowLoadedCommand}" />
</interactivity:Interaction.Behaviors>

In my View Model:

private DelegateCommand _WindowLoadedCommand;

public DelegateCommand WindowLoadedCommand
{
    get
    {
        return _WindowLoadedCommand;
    }
    private set
    {
        _WindowLoadedCommand = value;
    }
}

public ShellViewModel()
{
    WindowLoadedCommand = new DelegateCommand(WindowLoadedAction);
}

protected void WindowLoadedAction()
{
    ...
}

My attached behavior:

public class WindowLoadedBehavior : Behavior<FrameworkElement>
{
    [SuppressMessage("Microsoft.StyleCop.CSharp.MaintainabilityRules", "SA1401:FieldsMustBePrivate", Justification = "Dependency Property.  Allow public.")]
    public static DependencyProperty LoadedCommandProperty = DependencyProperty.Register("LoadedCommand", typeof(ICommand), typeof(WindowLoadedBehavior), new PropertyMetadata(null));

    public ICommand LoadedCommand
    {
        get { return (ICommand)GetValue(LoadedCommandProperty); }
        set { SetValue(LoadedCommandProperty, value); }
    }

    protected override void OnAttached()
    {
        base.OnAttached();

        AssociatedObject.Loaded += AssociatedObject_Loaded;
    }

    protected override void OnDetaching()
    {
        AssociatedObject.Loaded -= AssociatedObject_Loaded;

        base.OnDetaching();
    }

    private void AssociatedObject_Loaded(object sender, RoutedEventArgs e)
    {
        if (LoadedCommand != null)
            LoadedCommand.Execute(null);
    }
}

The OnAttached, AssociatedObject_Loaded and LoadedCommand get are all firing, but the LoadedCommand set is not firing and, obviously, the WindowLoadedCommand isn't firing. Any clue what I can do to get this working?

解决方案

There are a few options. A couple of them listed here:

how to call a window's Loaded event in WPF MVVM?

However, in the off chance that you or anyone else cares that you are spending several hours to complete a task that should have taken 30 seconds, you might want to try this instead.

public MainWindow()
{
    InitializeComponent();

    this.Loaded += new RoutedEventHandler(MainWindow_Loaded);
}

void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
    ShellViewModel.Instance.WindowLoadedCommand.Execute(null);
}

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