c# - MenuItem 可见性基于子菜单项状态

Question

我有一个基于 MVVM 的 WPF 上下文菜单，并希望将菜单项的可见性绑定(bind)到 IsEnabled其子菜单项的属性。问题是:根MenuItem始终可见，即使所有子菜单项都被禁用。但是在菜单项上移动光标使其隐藏，我真的不知道为什么。



这是我的 xaml 代码:

<MenuItem x:Name="SelectionMenuItem" Header="{x:Static language:CommonRes.Selection}">
    <MenuItem.Visibility>
        <MultiBinding Converter="{StaticResource AnyBoolToVisibilityConverter}">
            <Binding
                ElementName="SelectGroupMenuItem"
                Mode="OneWay"
                Path="IsEnabled" />
            <Binding
                ElementName="SelectGraphMenuItem"
                Mode="OneWay"
                Path="IsEnabled" />
        </MultiBinding>
    </MenuItem.Visibility>

    <MenuItem
        x:Name="SelectGroupMenuItem"
        Command="{Binding SelectGroupCommand}"
        Header="{x:Static language:CommonRes.Group}"
        Visibility="{Binding IsEnabled, Converter={StaticResource BoolToVisibilityConverter}, RelativeSource={RelativeSource Self}}" />
    <MenuItem
        x:Name="SelectGraphMenuItem"
        Command="{Binding SelectGraphCommand}"
        Header="{x:Static language:CommonRes.ObjectGraph}"
        Visibility="{Binding IsEnabled, Converter={StaticResource BoolToVisibilityConverter}, RelativeSource={RelativeSource Self}}" />
</MenuItem>

和我的转换器的代码

public class AnyBoolToVisibilityConverter : IMultiValueConverter
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="values"></param>
    /// <param name="targetType"></param>
    /// <param name="parameter"></param>
    /// <param name="culture"></param>
    /// <returns></returns>
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if(!values.All(val => val is bool))
            return Visibility.Collapsed;

        return values.Any(val => (bool)val) ? Visibility.Visible : Visibility.Collapsed;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="value"></param>
    /// <param name="targetTypes"></param>
    /// <param name="parameter"></param>
    /// <param name="culture"></param>
    /// <returns></returns>
    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException($"ConvertBack not Supported for {nameof(AnyBoolToVisibilityConverter)}");
    }
}

我希望你们中的一些人可以帮助我找到问题。

非常感谢。

Answer 1

似乎 Items的 Popup在 Popup 之前不会评估他们的绑定(bind)调用IsSubmenuOpenChanged回调和调用 CommandManager.InvalidateRequerySuggested()在 IsSubmenuOpen 之后属性已更改 (Source)。

所以我最终得到了另一个根命令MenuItem验证所有子菜单命令的 CanExecute。