处理与WPF / MVVM光工具包中的窗口关闭事件 [英] Handling the window closing event with WPF / MVVM Light Toolkit

问题描述

我想处理关闭事件（当用户点击右上角的X按钮），以最终显示一个确认信息和/或取消关闭我的窗口。

I'd like to handle the "Closing" event (when a user clicks the upper right 'X' button) of my window in order to eventually display a confirm message or/and cancel the closing.

我知道如何在$ C $这样做C-背后：订阅窗口关闭事件再使用CancelEventArgs.Cancel财产

I know how to do this in the code-behind : subscribe to the "Closing" event of the window then use the "CancelEventArgs.Cancel" property.

但我使用MVVM所以我不知道它的好方法。

But I'm using MVVM so I'm not sure it's the good approach.

我想好办法是Closing事件到命令绑定在我的ViewModel。

I think the good approach would be to bind the Closing event to a Command in my ViewModel.

我试过了：

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

在我的ViewModel关联RelayCommand，但它不能正常工作（不执行命令的code）。

With an associated RelayCommand in my ViewModel but it doesn't work (the command's code is not executed).

推荐答案

我只想处理程序中查看构造关联：

I would simply associate the handler in the View constructor:

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

然后将处理程序添加到视图模型：

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

在这种情况下，您可以通过使用更精细的图案更间接（ XML 加命令模式的5个额外的线路），除了获得准确的复杂性无关。

In this case, you gain exactly nothing except complexity by using a more elaborate pattern with more indirection (5 extra lines of XML plus command pattern).

零code-背后的口号本身不是目的，关键是为从视图分离视图模型。即使在事件查看的code-背后所绑定的视图模型不依赖于查看和闭幕逻辑的可以是单元测试。

The "zero code-behind" mantra is not the goal in itself, the point is to decouple ViewModel from the View. Even when the event is bound in code-behind of the View, the ViewModel does not depend on the View and the closing logic can be unit-tested.

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