在新窗口中打开的TabItem

Question

在我的应用程序有以下附加属性在加载ICommand或UserControl调用一个Window：

public static readonly DependencyProperty LoadedCommandProperty = DependencyProperty.RegisterAttached(
    "LoadedCommand", typeof(ICommand), typeof(UserControlExtensions), new PropertyMetadata(null, OnLoadedCommandChanged));

private static void OnLoadedCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    ContentControl userControl = d as ContentControl;
    if (userControl == null)
        return;

    if (e.NewValue is ICommand)
    {
        userControl.Loaded += UserControlOnLoaded;
    }
}

private static void UserControlOnLoaded(object sender, RoutedEventArgs e)
{
    ContentControl userControl = sender as ContentControl;
    if (userControl == null)
        return;

    ICommand command = GetLoadedCommand(userControl);
    command.Execute(GetLoadedCommandParameter(userControl));
}

public static void SetLoadedCommand(DependencyObject element, ICommand value)
{
    element.SetValue(LoadedCommandProperty, value);
}

public static ICommand GetLoadedCommand(DependencyObject element)
{
    return (ICommand) element.GetValue(LoadedCommandProperty);
}

public static readonly DependencyProperty LoadedCommandParameterProperty = DependencyProperty.RegisterAttached(
    "LoadedCommandParameter", typeof(object), typeof(UserControlExtensions), new PropertyMetadata(default(object)));

public static void SetLoadedCommandParameter(DependencyObject element, object value)
{
    element.SetValue(LoadedCommandParameterProperty, value);
}

public static object GetLoadedCommandParameter(DependencyObject element)
{
    return (object) element.GetValue(LoadedCommandParameterProperty);
}

这只是正常工作。在我的意见我称之为一个UserControl，如：

AttachedProperties:UserControlExtensions.LoadedCommand="{Binding ViewLoadedCommand}"

而在视图模型的ICommand将被调用。

现在我已经实现了一个功能，我可以在Button的标题点击一个TabItem，并在新窗口中打开此TabItem的内容。 （就像在Visual Studio脱位一个选项卡）。

所以我用下面的代码：

private void OpenInWindowButtonOnClick(object sender, RoutedEventArgs e)
{
    Button button = sender as Button;
    if (button == null)
        return;

    TabItem tabItem = button.Tag as TabItem;
    if (tabItem == null)
        return;

    string title = string.Empty;

    ContentControl headerContent = tabItem.Header as ContentControl;
    if (headerContent != null)
    {
        title = headerContent.Content.ToString();
    }

    string workspaceId = tabItem.Tag as string;

    TabItem workspaceTab = WorkspaceTab.Items.OfType<TabItem>()
        .FirstOrDefault(ti => ti.Tag is string && (string)ti.Tag == workspaceId);
    if (workspaceTab != null)
    {
        WorkspaceWindow workspaceWindow = new WorkspaceWindow(tabItem);
        workspaceWindow.Content = workspaceTab.Content;

        workspaceWindow.Width = (workspaceTab.Content as FrameworkElement).ActualWidth;
        workspaceWindow.Height = (workspaceTab.Content as FrameworkElement).ActualHeight;

        workspaceWindow.Title = title;
        workspaceWindow.Closing += WorkspaceWindowOnClosing;
        workspaceWindow.Show();
        workspaceWindows.Add(workspaceId, workspaceWindow);
        WorkspaceTab.Items.Remove(workspaceTab);
    }
}

这还只是正常工作。

我现在的问题是，如果我打开一个新标签（女巫还包含TabControl其中TabItems有装载-attachedproperty）和移动该标签与上面的代码的新窗口：当我切换到加载的命令不会叫查看使用加载-attachedproperty其中。

如果我调试attachedproperty我可以看到，该OnLoadedCommandChanged正确调用，但UserControlOnLoaded不叫。如果我没有在新窗口中打开TabItem的UserControlOnLoaded正确调用。

任何想法，为什么子页面的加载事件，如果我移动TabItem到一个新的Window不被解雇？

Answer 1

问题是行内WorkspaceTab.Items.Remove(workspaceTab);

这条线将删除TabItem的TabControl，似乎WPF这里做某种清理。

我已经解决了这个问题，只是设置Visibility到隐藏的TabItem。