如果在Windows Phone 7应用程序(C#,silverlight,xaml)中为空,如何使textBlock自动隐藏?
我知道WPF有一个类似的问题,但它似乎不适用于silverlight。
答案 0 :(得分:8)
您可以使用转换器:
<TextBlock Visibility="{Binding YourString, Converter={StaticResource LengthConverter}" />
<UserControl.Resources>
<converter:LengthConverter x:Key="LengthToVisibilityConverter" />
</UserControl.Resources>
然后转换器是:
public class LengthToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string text = (string)value;
return text.Length > 0 ? Visibility.Visible : Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
您可以通过直接绑定到文本长度来使其更加清晰:
<TextBlock Visibility="{Binding YourString.Length, Converter={StaticResource LengthConverter}" />
在这种情况下,转换器变为:
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
int length = (int)value;
return length > 0 ? Visibility.Visible : Visibilty.Collapsed;
}
在此处了解有关转换器的更多信息:http://msdn.microsoft.com/en-us/library/system.windows.data.binding.converter(v=vs.110).aspx