如何在 WPF TabControl 中取消选项卡更改

我在 SO 上发现了有关此问题的多个问题，但是我仍然无法找到切实可行的解决方案.这是我在阅读答案后想到的.

I have found multiple questions about this problem on SO, however I still can't quite get a realiable solution. Here is what I came up with after reading the answers.

XML:

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="300" Width="300" x:Name="this">
    <TabControl IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding Tabs, ElementName=this}" x:Name="TabControl"/>
</Window>

背后的代码:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        var tabs = new ObservableCollection<string> {"Tab1", "Tab2", "Tab3"};
        Tabs = CollectionViewSource.GetDefaultView(tabs);
        Tabs.CurrentChanging += OnCurrentChanging;
        Tabs.CurrentChanged += OnCurrentChanged;
        Tabs.MoveCurrentToFirst();
        CurrentTab = tabs.First();
    }

    private void OnCurrentChanging(object sender, CurrentChangingEventArgs e)
    {
        //only show message box when tab is changed by user input
        if (!_cancelTabChange)
        {
            if (MessageBox.Show("Change tab?", "Message", MessageBoxButton.YesNo) == MessageBoxResult.No)
            {
                _cancelTabChange = true;
                return;
            }
        }
        _cancelTabChange = false;
    }

    private void OnCurrentChanged(object sender, EventArgs e)
    {
        if (!_cancelTabChange)
        {
            //Update current tab property, if user did not cancel transition
            CurrentTab = (string)Tabs.CurrentItem;
        }
        else
        {
            //navigate back to current tab otherwise
            Dispatcher.BeginInvoke(new Action(() => Tabs.MoveCurrentTo(CurrentTab)));
        }
    }

    public string CurrentTab { get; set; }

    public static readonly DependencyProperty TabsProperty = DependencyProperty.Register("Tabs", typeof(ICollectionView), typeof(MainWindow), new FrameworkPropertyMetadata(default(ICollectionView)));
    public ICollectionView Tabs
    {
        get { return (ICollectionView)GetValue(TabsProperty); }
        set { SetValue(TabsProperty, value); }
    }

    private bool _cancelTabChange;
}

基本上我想显示一条确认消息，当用户导航到不同的选项卡时，如果他点击否" - 中止转换.这段代码虽然不起作用.如果您多次单击Tab2"，每次在消息框中选择否"，它都会在某些时候停止工作:事件停止触发.如果您单击Tab3"，事件将再次触发，但如果您选择是"，它将打开第二个选项卡而不是第三个选项卡.我无法弄清楚 wtf 正在进行中.:)

Basically I want to display a confirmation message, when user navigates to different tab, and if he clicks "no" - abort the transition. This code does not work though. If you click multiple times on "Tab2", each time choosing "no" in message box, at some point it stops working: events stop triggering. Event will trigger again if you click on "Tab3", but if you choose "yes" it opens second tab and not third. I am having trouble figuring out wtf is going on. :)

有人看到我的解决方案中有错误吗?或者当用户切换选项卡时，是否有更简单的方法来显示确认消息?我也愿意使用任何具有适当 SelectionChanging 事件的开源选项卡控件.虽然我找不到.

Does anyone see a bug in my solution? Or is there an easier way to display a confirmation message, when user switches tabs? I am also willing to use any opensource tab control, which does have a proper SelectionChanging event. I could not find any though.

我使用的是 .Net 4.0.

I am using .Net 4.0.

如果我将消息框注释掉:

If I comment the message box out:

private void OnCurrentChanging(object sender, CurrentChangingEventArgs e)
{
    //only show message box when tab is changed by user input
    if (!_cancelTabChange)
    {
        //if (MessageBox.Show("Change tab?", "Message", MessageBoxButton.YesNo) == MessageBoxResult.No)
        //{
            Debug.WriteLine("Canceled");
            _cancelTabChange = true;
            return;
        //}
    }
    _cancelTabChange = false;
}

一切正常.奇怪.