不调用OnDetaching函数的行为

Question

我有WPF behavior特定的控制权.当我关闭保持控件的窗口时,OnDetaching不会调用该函数.

行为继续存在(因为它注册的事件),虽然窗口不再存在(内存泄漏).

为什么OnDetaching功能没有解雇****,我该如何解决？

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

     this.AssociatedObject.MouseLeftButtonDown += AssociatedObject_PlotAreaMouseLeftButtonDown;
     this.AssociatedObject.MouseLeftButtonUp += AssociatedObject_PlotAreaMouseLeftButtonUp;
     this.AssociatedObject.MouseMove += AssociatedObject_PlotAreaMouseMove;
}

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

     this.AssociatedObject.MouseLeftButtonDown -= AssociatedObject_PlotAreaMouseLeftButtonDown;
     this.AssociatedObject.MouseLeftButtonUp -= AssociatedObject_PlotAreaMouseLeftButtonUp;
     this.AssociatedObject.MouseMove -= AssociatedObject_PlotAreaMouseMove;
}

Answer 1

OnAttached当XAML解析器解析XAML并创建一个行为实例时,会调用该行为,该行为将添加到作为DependencyAttached属性公开的目标控件的BehaviorCollection中.

但是,如果处理视图,处理(行为集合)处理,它将永远不会触发OnDetaching方法.

如果行为未正确清理,则GC不会收集该行为,并且还会在该集合中保存BehaviorCollection和其他行为.这些行为旨在扩展AssociatedObject,只要您订阅AssociatedObject事件就好了,因为AssociatedObject(发布者)将会死亡,您的行为将由垃圾收集器收集.

一个很好的来源.

另一种方法是处理窗口中的"关闭"事件(当用户点击右上方的"X"按钮时)OnDetaching .

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

然后在View构造函数中关联处理程序:

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

并将处理程序添加到ViewModel:

public void OnWindowClosing(object sender, CancelEventArgs e) 
{
   // Cancel, OnDetaching, etc
}