在ListView的ItemTemplate中使用的AvalonEdit中的挂钩命令不起作用

Question

我在我的项目中使用了AvalonEdit控件.当我使用Ctrl + C或Ctrl + V等快捷键时,相关的复制/粘贴命令可以正常工作.我决定在上下文菜单中使用这些命令以获得更多可用性,因为有些用户习惯于右键单击而不是快捷方式.我使用以下XAML代码进行控制:

<avalonedit:TextEditor.ContextMenu>
    <ContextMenu>
         <MenuItem Command="Undo" />
         <MenuItem Command="Redo" />
         <Separator/>
         <MenuItem Command="Cut" />
         <MenuItem Command="Copy" />
         <MenuItem Command="Paste" />
     </ContextMenu>
</avalonedit:TextEditor.ContextMenu>

但是当我运行程序时,这些命令总是在上下文菜单中显示为禁用,如下所示:

当我第一次遇到这个问题时,我发布了一个不同的问题但是在MD.Unicorn的帮助下(正如你在下面的评论中看到的)我意识到当你将AvalonEdit放在ListBox或ListView命令的ItemTemplate中时不起作用.

在MD.unicorn的帮助下,我创建了以下测试代码来重现结果:

ViewModel类和数据模板的简单类

public class MyViewModel : INotifyPropertyChanged
{
    public MyViewModel()
    {
        collection = new ObservableCollection<myClass>();
        mc = new myClass();
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propName)
    {
        var h = PropertyChanged;
        if (h != null)
            h(this, new PropertyChangedEventArgs(propName));
    }

    public ObservableCollection<myClass> collection { get; set; }
    public myClass mc { get; set; }
}

public class myClass
{
    public string text { get; set; }
}

public partial class MainWindow : Window
{
    MyViewModel _viewModel = new MyViewModel();

    public MainWindow()
    {
        InitializeComponent();

        this.DataContext = _viewModel;
    }
 }

和MainWindow的XAML代码

<Window.Resources>
    <DataTemplate DataType="{x:Type local:myClass}">
        <StackPanel>
        <avalonedit:TextEditor x:Name="xmlMessage" 
        SyntaxHighlighting="XML" ShowLineNumbers="True"  >
            <avalonedit:TextEditor.ContextMenu>
                <ContextMenu>
                    <MenuItem Command="Undo" />
                    <MenuItem Command="Redo" />
                    <Separator/>
                    <MenuItem Command="Cut" />
                    <MenuItem Command="Copy" />
                    <MenuItem Command="Paste" />
                </ContextMenu>
            </avalonedit:TextEditor.ContextMenu>
        </avalonedit:TextEditor>
        <TextBox Text="test" />
        </StackPanel>
    </DataTemplate>
</Window.Resources>
<DockPanel>
    <ListView ItemsSource="{Binding collection}" />
    <ContentControl Content="{Binding mc}" />
</DockPanel>

如果您尝试此测试,您可以看到如果在内容控件上使用DataTemplate,它在上下文菜单中的命令绑定工作正常,但在ListViewItem中它们被禁用.另请注意,DataTemplate中的上下文菜单适用于TextBox,并显示ListView本身并不会破坏命令链.

如何修复上下文菜单并连接到listView项目中的控制命令？

Answer 1

这就是我过去遇到的类似问题 - 我希望它对人们有用(这个通用逻辑可以应用于各种各样的Avalon编辑器相关问题)......

实际发生的可能是Avalon的错(与之结合ListItem等).它弄乱了鼠标操作,我猜测焦点(应该在TextArea命令和CanExecute工作上.

该mouse handling是问题-因为如果你只需要按下windows context menu按键就弹出启用命令的普通菜单.Avalon编辑器有一个复杂的鼠标/键处理(很难做出一个好的编辑器) - 而在键盘上它focus在TextArea上做了一个明确的' '.您还可以通过在CanCutOrCopy方法上设置断点 (Editing/EditingCommandHandler.cs,下载Avalon源)来实际处理问题 ApplicationCommands.Copy.对于"键盘"菜单,它首先进入,然后弹出.对于'鼠标',它会弹出 - 然后在退出时检查CanExecute(输入该方法).那都错了!

和勘误......

您自己的命令没有问题,只需正常公开您的命令,一切都应该有效.

对于ApplicationCommands(即RoutedCommand)它没有正确接线 - 并且Execute,CanExecute不要去它应该的地方,即TextArea.要纠正你需要rewire将命令放入你自己的包装器 - 并且基本上调用TextArea处理 - 这只是几行代码,但这是一个必要的步骤(我不认为有一个更'美丽'的解决方案,没有修复Avalon代码 - 这可能是一种痛苦,从未在我脑海中浮现.

(所有都是基于你的例子 - 填写我遗漏的空白)你的XAML:

<Window.Resources>
    <DataTemplate DataType="{x:Type my:myClass}">
        <StackPanel>
            <my:AvalonTextEditor x:Name="xmlMessage" SyntaxHighlighting="XML" ShowLineNumbers="True" EditText="{Binding text}" >
                <my:AvalonTextEditor.ContextMenu>
                    <ContextMenu x:Name="mymenu1">
                        <ContextMenu.Resources>
                            <Style TargetType="MenuItem">
                                <Setter Property="CommandParameter" Value="{Binding Path=., RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}"/>
                            </Style>
                        </ContextMenu.Resources>
                        <MenuItem Header="My Copy" Command="{Binding CopyCommand}" />
                        <MenuItem Header="My Paste" Command="{Binding PasteCommand}" />
                        <MenuItem Header="My Cut" Command="{Binding CutCommand}" />
                        <MenuItem Header="My Undo" Command="{Binding UndoCommand}" />
                        <MenuItem Header="My Redo" Command="{Binding RedoCommand}" />
                        <Separator />
                        <MenuItem Command="Undo" />
                        <MenuItem Command="Redo" />
                        <Separator/>
                        <MenuItem Command="Cut" />
                        <MenuItem Command="Copy" />
                        <MenuItem Command="Paste" />
                    </ContextMenu>
                </my:AvalonTextEditor.ContextMenu>
            </my:AvalonTextEditor>
        </StackPanel>
    </DataTemplate>
</Window.Resources>
<StackPanel>
    <DockPanel>
        <ListView ItemsSource="{Binding collection}" />
        <ContentControl Content="{Binding mc}" />
    </DockPanel>
</StackPanel>

后面的代码 - 视图模型:(
注意:我按照你的命名离开了命名 - 但请不要使用小型大写的道具:)

public class MyViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public MyViewModel()
    {
        collection = new ObservableCollection<myClass>(new[]
        {
            new myClass{ text = "some more test - some more test - some more test - some more test - some more test - some more test - some more test - some more test - some more test - " },
            new myClass{ text = "test me test me = test me test me = test me test me = test me test me = test me test me = test me test me = " },
            new myClass{ text = "test again - test again - test again - test again - test again - " },
            new myClass{ text = "test again - test again - " },
            new myClass{ text = "test again - " },
            new myClass{ text = "test" },
        });
        mc = new myClass();
    }
    public ObservableCollection<myClass> collection { get; set; }
    public myClass mc { get; set; }
}

public class myClass
{
    public string text { get; set; }

    AvalonRelayCommand _copyCommand;
    public AvalonRelayCommand CopyCommand
    { get { return _copyCommand ?? (_copyCommand = new AvalonRelayCommand(ApplicationCommands.Copy) { Text = "My Copy" }); } }

    AvalonRelayCommand _pasteCommand;
    public AvalonRelayCommand PasteCommand
    { get { return _pasteCommand ?? (_pasteCommand = new AvalonRelayCommand(ApplicationCommands.Paste) { Text = "My Paste" }); } }

    AvalonRelayCommand _cutCommand;
    public AvalonRelayCommand CutCommand
    { get { return _cutCommand ?? (_cutCommand = new AvalonRelayCommand(ApplicationCommands.Cut) { Text = "My Cut" }); } }

    AvalonRelayCommand _undoCommand;
    public AvalonRelayCommand UndoCommand
    { get { return _undoCommand ?? (_undoCommand = new AvalonRelayCommand(ApplicationCommands.Undo) { Text = "My Undo" }); } }

    AvalonRelayCommand _redoCommand;
    public AvalonRelayCommand RedoCommand
    { get { return _redoCommand ?? (_redoCommand = new AvalonRelayCommand(ApplicationCommands.Redo) { Text = "My Redo" }); } }
}

(注意:只需连接Window.DataContext到视图模型,就像你所做的那样)

这需要两个自定义类来包装.

public class AvalonTextEditor : TextEditor
{
    #region EditText Dependency Property

    public static readonly DependencyProperty EditTextProperty =
        DependencyProperty.Register(
        "EditText",
        typeof(string),
        typeof(AvalonTextEditor),
        new UIPropertyMetadata(string.Empty, EditTextPropertyChanged));
    private static void EditTextPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        AvalonTextEditor editor = (AvalonTextEditor)sender;
        editor.Text = (string)e.NewValue;
    }
    public string EditText
    {
        get { return (string)GetValue(EditTextProperty); }
        set { SetValue(EditTextProperty, value); }
    }

    #endregion

    #region TextEditor Property

    public static TextEditor GetTextEditor(ContextMenu menu) { return (TextEditor)menu.GetValue(TextEditorProperty); }
    public static void SetTextEditor(ContextMenu menu, TextEditor value) { menu.SetValue(TextEditorProperty, value); }
    public static readonly DependencyProperty TextEditorProperty =
        DependencyProperty.RegisterAttached("TextEditor", typeof(TextEditor), typeof(AvalonTextEditor), new UIPropertyMetadata(null, OnTextEditorChanged));
    static void OnTextEditorChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
    {
        ContextMenu menu = depObj as ContextMenu;
        if (menu == null || e.NewValue is DependencyObject == false)
            return;
        TextEditor editor = (TextEditor)e.NewValue;
        NameScope.SetNameScope(menu, NameScope.GetNameScope(editor));
    }

    #endregion

    public AvalonTextEditor()
    {
        this.Loaded += new RoutedEventHandler(AvalonTextEditor_Loaded);
    }

    void AvalonTextEditor_Loaded(object sender, RoutedEventArgs e)
    {
        this.ContextMenu.SetValue(AvalonTextEditor.TextEditorProperty, this);
    }
}

public class AvalonRelayCommand : ICommand
{
    readonly RoutedCommand _routedCommand;
    public string Text { get; set; }
    public AvalonRelayCommand(RoutedCommand routedCommand) { _routedCommand = routedCommand; }
    public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } }
    public bool CanExecute(object parameter) { return _routedCommand.CanExecute(parameter, GetTextArea(GetEditor(parameter))); }
    public void Execute(object parameter) { _routedCommand.Execute(parameter, GetTextArea(GetEditor(parameter))); }
    private AvalonTextEditor GetEditor(object param)
    {
        var contextMenu = param as ContextMenu;
        if (contextMenu == null) return null;
        var editor = contextMenu.GetValue(AvalonTextEditor.TextEditorProperty) as AvalonTextEditor;
        return editor;
    }
    private static TextArea GetTextArea(AvalonTextEditor editor)
    {
        return editor == null ? null : editor.TextArea;
    }
}

笔记:

EditText只是一个依赖属性 - 能够bind文本(你的text) - 这是Avalon的缺点.这里只是为了好玩,但你可能需要它,所以我把它留在了.

使用AvalonRelayCommand重新布线应用路由命令-用于其他的东西用自己的命令执行.这两个类是核心.

您需要使用AvalonTextEditor而不是TextEditor - 这只是一个小包装 - 来ContextMenu与TextEditor(除了其他问题,菜单项suffering来自缺乏visual tree- 并且您无法轻易获得任何控件).我们需要TextEditor从CommandParameter(它设置为a ContextMenu)得到一个ref .这可以通过一些附件属性(没有覆盖TextEditor)完成,但这样看起来更干净.

在XAML方面 - 只是一些小的改动 - 使用包装器编辑器 - 你有一个MenuItem样式,injects每个命令的正确参数(你可以做其他方式,这是更好的).

它不是hack- 我们只是通过手动调用TextArea命令处理来缩短鼠标处理的缺点.这就是它.

请享用!