绑定转换器参数 [英] Binding ConverterParameter

问题描述

有没有一种方法可以在 Style 中做到这一点:

Is there a way I could do this in a Style:

<Style TargetType="FrameworkElement">
    <Setter Property="Visibility">
        <Setter.Value>
            <Binding Path="Tag"
                RelativeSource="{RelativeSource AncestorType=UserControl}"
                Converter="{StaticResource AccessLevelToVisibilityConverter}"
                ConverterParameter="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Tag}" />                        
        </Setter.Value>
    </Setter>
</Style>

我只需要将顶级父级的 Tag 和控件本身的 Tag 发送到我的转换器类.

I simply need to send the Tag of top-level parent and the Tag of control itself to my converter class.

推荐答案

无法绑定 ConverterParameter 属性，因为它不是依赖属性.

The ConverterParameter property can not be bound because it is not a dependency property.

因为 Binding 不是从 DependencyObject 派生的，所以它的任何属性都不能是依赖属性.因此，一个 Binding 永远不能成为另一个 Binding 的目标对象.

Since Binding is not derived from DependencyObject none of its properties can be dependency properties. As a consequence, a Binding can never be the target object of another Binding.

然而，有一个替代解决方案.您可以使用 MultiBinding 使用 多值转换器 而不是普通的绑定:

There is however an alternative solution. You could use a MultiBinding with a multi-value converter instead of a normal Binding:

<Style TargetType="FrameworkElement">
    <Setter Property="Visibility">
        <Setter.Value>
            <MultiBinding Converter="{StaticResource AccessLevelToVisibilityConverter}">
                <Binding Path="Tag" RelativeSource="{RelativeSource Mode=FindAncestor,
                                                     AncestorType=UserControl}"/>
                <Binding Path="Tag" RelativeSource="{RelativeSource Mode=Self}"/>
            </MultiBinding>
        </Setter.Value>
    </Setter>
</Style>

多值转换器获取源值数组作为输入:

The multi-value converter gets an array of source values as input:

public class AccessLevelToVisibilityConverter : IMultiValueConverter
{
    public object Convert(
        object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        return values.All(v => (v is bool && (bool)v))
            ? Visibility.Visible
            : Visibility.Hidden;
    }

    public object[] ConvertBack(
        object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

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