WPF:通过字符串内容绑定可见性

Question

好的,这是我的XAML:

<TextBlock Text="{Binding Path=InstanceName}"></TextBlock>

如果InstanceName是null或空字符串,我想要Visibility="Collapsed".否则我想要Visibility="Visible".我该怎么办？

Answer 1

您可以使用ValueConverter:

<TextBlock 
     Visibility="{Binding InstanceName, Converter={local:StringNullOrEmptyToVisibilityConverter}}" 
     Text="{Binding InstanceName}"/>

使用以下代码隐藏:

public class StringNullOrEmptyToVisibilityConverter : System.Windows.Markup.MarkupExtension, IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return string.IsNullOrEmpty(value as string) 
            ? Visibility.Collapsed : Visibility.Visible;
    }
    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
    public override object ProvideValue(IServiceProvider serviceProvider)
    {            
        return this;
    }
}