Question

TextBlock只有在选中CheckBox（x:Name=DisplaySubscriber）或Binding字符串不为空或为空时才可见。

这是我的方法：

<CheckBox Content="Display Subscriber" x:Name="DisplaySubscriber" />

<TextBlock Text="{Binding Path=SubscriberString, Mode=OneWay}" >
        <TextBlock.Visibility>
            <MultiBinding>
                <Binding ElementName="DisplaySubscriber" Path="IsChecked" Mode="OneWay" Converter="{StaticResource BooleanToVisibleConverter}"/>                        
                <Binding Path="SubscriberString" Mode="OneWay" Converter="{StaticResource StringIsNullEmptyConverter}"/>    
            </MultiBinding>
        </TextBlock.Visibility>
</TextBlock>

但我收到了这个错误：

在'System.Windows.Data.MultiBinding'上提供一个值异常。

Answer 1

转换器：

openInstalledApp(<your_context>,"com.google.android.youtube");

XAML：在资源中定义转换器：

public class TextBlockVisibilityConverter : IMultiValueConverter
{
    #region IMultiValueConverter Members

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if((value[0] != null && (bool)value[0]) || (value[1]!=null && !String.IsNullOrEmpty(value[1].ToString())))
        {
            return Visibility.Visible;
        }    
        return Visibility.Collapsed;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
    #endregion
}

在多重绑定中使用它

<local:TextBlockVisibilityConverter x:Key="TextBlockVisibilityConverter"/>

TextBlock MultiBinding抛出异常

1 个答案: