WPF + Caliburn Micro + MVVM：TabItem 处理

Question

我正在尝试使用 WPF、Caliburn Micro 和 MVVM 模式制作一个包含 tabcontrol 的弹出窗口，在这种情况下无需使用后面的代码。 tabcontrol 包含超过 1 个 tabitem。在 SO 中挖掘了一些线程一段时间后，我结合了找到的解决方案，可以创建弹出窗口并用 tabcontrol 及其 tabitems (I take it from this thread) 填充它。

问题： tabitems 显示来自视图模型的内容（文本），但不显示来自视图的内容。请看这里附上的代码。

预期我希望将文本“Tab Item 1”作为 TabItem1 标题，将文本“Selection One”作为 TabItem1 中的内容。现在，TabItems 的标题和内容都包含相同的文本“Tab Item 1”。

我错过了什么吗？我在这里附上代码。请随意更改代码。任何提示都非常感谢。

代码序列：

• TabItem1、TabItem2 视图和视图模型
• ITabItem
• 弹出窗口视图和视图模型
• AppBootstrapper、Shell 视图和视图模型

TabItem1ViewModel（TabItem2ViewModel 内容相同）

public class TabItem1ViewModel : Screen, ITabItem
{
    public TabItem1ViewModel() => DisplayName = "Tab Item 1";
}

注意： 在下面的 TabItem 视图中，我使用 Label 来显示文本“Selection One”，但该文本根本没有出现。只有视图模型中定义的显示名称“Tab Item 1”显示为 TabItem1 的内容

TabItem1View（TabItem2View 内容相同）

<UserControl
    x:Class="CmTabControl.Views.TabItem1View"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    d:DesignHeight="450"
    d:DesignWidth="800"
    mc:Ignorable="d">
    <Grid>
        <TabItem x:Name="TabItem1" Header="{Binding Path=DisplayName}">
            <Grid x:Name="TabItem1ContentGrid">
                <Label HorizontalAlignment="Left"                     
                    VerticalAlignment="Top"
                    Content="Selection One" />
            </Grid>
        </TabItem>
    </Grid>
</UserControl>

ITabItem（是的，只是空界面）

public interface ITabItem : IScreen
{
}

PopUpViewModel

public class PopUpViewModel : Screen
{
    public PopUpViewModel()
    {
        TabItems.Add(new TabItem1ViewModel());
        TabItems.Add(new TabItem2ViewModel());
    }

    private readonly BindableCollection<ITabItem> _tabItems = new BindableCollection<ITabItem>();
    public BindableCollection<ITabItem> TabItems
    {
        get => _tabItems;
        set
        {
            if (_tabItems == null)
            {
                return;
            }
            _tabItems.Clear();
            _tabItems.AddRange(value);
            NotifyOfPropertyChange(() => TabItems);
        }
    }
}

弹出视图

<Window
    x:Class="CmTabControl.Views.PopUpView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:CmTabControl.Views"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="PopUpView"
    Width="800"
    Height="450"
    mc:Ignorable="d">
    <Grid Margin="3,8,3,3" HorizontalAlignment="Stretch"
        VerticalAlignment="Stretch">
        <TabControl x:Name="TabItems" />
    </Grid>
</Window>

AppBootstrapper

public class AppBootstrapper : BootstrapperBase
{
    private readonly SimpleContainer _container = new SimpleContainer();

    public AppBootstrapper() => Initialize();
    protected override object GetInstance(Type serviceType, string key) => _container.GetInstance(serviceType, key);
    protected override IEnumerable<object> GetAllInstances(Type serviceType) => _container.GetAllInstances(serviceType);
    protected override void BuildUp(object instance) => _container.BuildUp(instance);

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

        _container.Singleton<IWindowManager, WindowManager>();
        _container.Singleton<IEventAggregator, EventAggregator>();
        _container.Singleton<ShellViewModel>();
        _container.PerRequest<PopUpViewModel>(); // Or Singleton if there'll only ever be one
    }

    protected override void OnStartup(object sender, StartupEventArgs e)
    {
        base.OnStartup(sender, e);
        DisplayRootViewFor<ShellViewModel>();
    }
}

ShellViewModel

public class ShellViewModel : Conductor<object>.Collection.AllActive
{
    private IWindowManager _windowManager;

    public ShellViewModel(PopUpViewModel popUpVm)
    {
        DisplayName = "Shell Window";
        PopUpViewModel = popUpVm;
    }

    public PopUpViewModel PopUpViewModel { get; set; }

    public sealed override void ActivateItem(object item) => base.ActivateItem(item);

    public void OpenPopUp()
    {
        ActivateItem(PopUpViewModel);
        if (_windowManager == null) _windowManager = new WindowManager();
        _windowManager.ShowDialog(PopUpViewModel, null, null);
    }

    public sealed override string DisplayName { get; set; }
}

ShellView

<UserControl
    x:Class="CmTabControl.Views.ShellView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    d:DesignHeight="300"
    d:DesignWidth="300"
    mc:Ignorable="d">
    <Grid Width="300" Height="300"
        HorizontalAlignment="Center" VerticalAlignment="Center">
        <Button x:Name="OpenPopUp" Width="100" Height="35"
            Content="Open Popup" />
    </Grid>
</UserControl>

添加： Live Visual Tree 的屏幕截图。

Answer 1

我找到了一个使用模板的解决方案：

PopUpViewModel添加SelectedTab：

public sealed class PopUpViewModel : Screen
{
    private readonly BindableCollection<ITabItem> _tabItems = new BindableCollection<ITabItem>();
    private IScreen _selectedTab;


    public PopUpViewModel()
    {
        DisplayName = "Popup";
        TabItems.Add(new TabItem1ViewModel());
        TabItems.Add(new TabItem2ViewModel());
        SelectedTab = TabItems.FirstOrDefault();
    }


    public BindableCollection<ITabItem> TabItems
    {
        get => _tabItems;
        set
        {
            if(_tabItems == null)
                return;
            _tabItems.Clear();
            _tabItems.AddRange(value);
            NotifyOfPropertyChange(() => TabItems);
        }
    }

    public IScreen SelectedTab
    {
        get => _selectedTab;
        set
        {
            _selectedTab = value;
            NotifyOfPropertyChange();
        }
    }
}

PopUpView：

<Grid Margin="3, 8, 3, 3"
      HorizontalAlignment="Stretch"
      VerticalAlignment="Stretch">
    <TabControl ItemsSource="{Binding TabItems}"
                SelectedItem="{Binding SelectedTab,
                               UpdateSourceTrigger=PropertyChanged}">
        <TabControl.ItemTemplate>
            <DataTemplate>
                <Label Content="{Binding DisplayName}" />
            </DataTemplate>
        </TabControl.ItemTemplate>
        <TabControl.ContentTemplate>
            <DataTemplate>
                <ContentControl cal:View.Model="{Binding}" />
            </DataTemplate>
        </TabControl.ContentTemplate>
    </TabControl>
</Grid>

现在您只需将 TabItem 内容添加到您的页面，TabItem1View：

<UserControl x:Class="WpfTestApp.Views.Tabs.TabItem1View"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:local="clr-namespace:WpfTestApp.Views.Tabs"
             mc:Ignorable="d"
             d:DesignHeight="450"
             d:DesignWidth="800">

    <Grid x:Name="TabItem1ContentGrid">
        <Label HorizontalAlignment="Left"
               VerticalAlignment="Top"
               Content="Selection One" />
    </Grid>
</UserControl>

编辑：

SelectedTab 就在那里，所以默认选择第一个选项卡。