c# - 在一个窗口中定义的 WPF CommandBindings 在另一个窗口中不可用

Question

我遇到了这个问题，我在 MainWindow 中定义了所有这些 CommandBindings，并且所述命令在该窗口中可用，可用于任何 Button 或 MenuItem。问题是，如果在其他窗口中命令绑定(bind)不可用(它始终为 false)，即使新窗口的所有者是 MainWindow。

You can see the problem here.

非常感谢任何帮助。

这是代码。

XAML 主窗口:

<Window x:Class="ContextMenuDialogProblem.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:ContextMenuDialogProblem"
        Title="MainWindow" Height="350" Width="525"
        FocusManager.FocusedElement="{Binding RelativeSource={x:Static RelativeSource.Self}, Mode=OneTime}">
    <Window.CommandBindings>
        <CommandBinding Command="local:LocalCommandManager.ShowDialogCommand" CanExecute="CanExecuteShowDialogCommand" Executed="ShowDialogCommandExecuted" />
    </Window.CommandBindings>
    <Window.ContextMenu>
        <ContextMenu>
            <MenuItem Command="local:LocalCommandManager.ShowDialogCommand" />
        </ContextMenu>
    </Window.ContextMenu>
    <Grid Background="Red">
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition />
        </Grid.RowDefinitions>
        <Button Grid.Row="0"
                Content="Open SubWindow"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                Padding="6"
                Click="Button_Click" />
        <Button Grid.Row="1"
                Content="Show Dialog Command Test"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                Padding="6"
                Command="local:LocalCommandManager.ShowDialogCommand" />
    </Grid>
</Window>

CS 主窗口:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void CanExecuteShowDialogCommand(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = true;
    }

    private void ShowDialogCommandExecuted(object sender, ExecutedRoutedEventArgs e)
    {
        MessageBox.Show("Show Dialog");   
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        Window wnd = new SubWindow() { Owner = this };
        wnd.Show();
    }
}

CS LocalCommandManager:

public static class LocalCommandManager
{
    private static object syncRoot = new object();

    private static RoutedUICommand _showDialogCommand;
    public static RoutedUICommand ShowDialogCommand
    {
        get
        {
            lock (syncRoot)
            {
                if (_showDialogCommand == null)
                    _showDialogCommand = new RoutedUICommand("Show Dialog", "ShowDialogCommand", typeof(LocalCommandManager));
                return _showDialogCommand;
            }
        }
    }
}

XAML 子窗口:

<Window x:Class="ContextMenuDialogProblem.SubWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:local="clr-namespace:ContextMenuDialogProblem"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="SubWindow" Height="300" Width="300">
    <Grid>
        <Button Command="local:LocalCommandManager.ShowDialogCommand" Content="Show Dialog" HorizontalAlignment="Center" VerticalAlignment="Center" Padding="6" />
    </Grid>
</Window>

Answer 1

CommandBindings 的范围仅限于定义它的元素，因此这种行为是完全正常的。如果你想在那里使用它，你必须将 CommandBinding 添加到 SubWindow。