WPF Visiblity绑定到具有多个变量的布尔表达式

Question

我有两个布尔,我想根据它们的值显示Image,如下所示:

   <Window.Resources>
    <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Window.Resources>

<Image Visibility="{Binding (Boolean1 && Boolean2),Converter={StaticResource BooleanToVisibilityConverter}}" />

注意Boolean1和Boolean2表达式.

Answer 1

&&XAML中没有定义运算符,但您可以绑定到多个属性并使用IMultiValueConverter:

<Image>
    <Image.Visibility>
        <MultiBinding Converter="{StaticResource YourMultiConverter}">
            <Binding Path="Boolean1" />
            <Binding Path="Boolean2" />
        </MultiBinding>
    </Image.Visibility>
</Image>

public class YourMultiValueConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        bool a = (bool)values[0];
        bool b = (bool)values[1];

        return a && b ? Visibility.Visible : Visibility.Collapsed;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

或者您可以使用Image具有条件的样式:

<Image>
    <Image.Style>
        <Style TargetType="Image">
            <Setter Property="Visibility" Value="Collapsed" />
            <Style.Triggers>
                <MultiDataTrigger>
                    <MultiDataTrigger.Conditions>
                        <Condition Binding="{Binding Boolean1}" Value="True" />
                        <Condition Binding="{Binding Boolean2}" Value="True" />
                    </MultiDataTrigger.Conditions>
                    <Setter Property="Visibility" Value="Visible" />
                </MultiDataTrigger>
            </Style.Triggers>
        </Style>
    </Image.Style>
</Image>

Answer 2

mm8 已经提供了正确的答案，但是稍有改进就是这个

public class LogicalAndConverter : IMultiValueConverter
{
    public IValueConverter FinalConverter{get;set;}

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        bool rtn = values.All(v=>(bool)v);

        if(FinalConverter==null)    
            return rtn;
        else
            return FinalConverter.Convert(rtn,targetType,parameter,culture);
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

这样您就可以使用不同的转换器，而无需重写多转换器

<local:LogicalAndConverter x:Key="LogicalAndConverter ">
    <local:LogicalAndConverter.FinalConverter>
        <BooleanToVisibilityConverter />
    </local:LogicalAndConverter.FinalConverter>
</local:LogicalAndConverter>