wpf 如何隐藏空的 TextBlock？
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How to hide the empty TextBlock?
提问by Boris
In the XAML provided below, I don't have the value for Phone sometimes. When that happens, the value is missing, but the TextBlockis still occupying the space in the panel. I want to hide empty TextBlocks from taking space in the StackPanel.
在下面提供的 XAML 中，有时我没有 Phone 的值。发生这种情况时，该值丢失，但TextBlock仍占据面板中的空间。我想隐藏空TextBlocks 以免占用StackPanel.
Here's the XAML:
这是 XAML：
<StackPanel>
<TextBlock Text="{Binding Path=FirstName}" />
<TextBlock Text="{Binding Path=LastName}" />
<TextBlock Text="{Binding Path=Phone}" />
<TextBlock Text="{Binding Path=Email}" />
</StackPanel>
I've read this article, but the accepted answer doesn't work for me:
我已经阅读了这篇文章，但接受的答案对我不起作用：
<StackPanel>
<TextBlock Text="{Binding Path=FirstName}" />
<TextBlock Text="{Binding Path=LastName}" />
<TextBlock Text="{Binding Path=Phone}">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="Text" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed" />
</Trigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
<TextBlock Text="{Binding Path=Email}" />
</StackPanel>
Am I making a mistake somewhere, or is the accepted answer wrong? What should I do to achieve my goal?
我是在某个地方犯了错误，还是接受的答案是错误的？我应该怎么做才能实现我的目标？
回答by CodeNaked
You probably need to use:
您可能需要使用：
<Style TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="Text" Value="">
<Setter Property="Visibility" Value="Collapsed" />
</Trigger>
</Style.Triggers>
</Style>
or maybe both:
或者两者兼而有之：
<Style TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="Text" Value="">
<Setter Property="Visibility" Value="Collapsed" />
</Trigger>
<Trigger Property="Text" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed" />
</Trigger>
</Style.Triggers>
</Style>
回答by Brad Cunningham
Instead of introducing a style just for this, for this sort of thing I tend to prefer using a converter that will handle a null or empty string.
而不是为此引入样式，对于这类事情，我倾向于使用一个转换器来处理 null 或空字符串。
<TextBlock Text="{Binding Foo}"
Visibility="{Binding Foo,
Converter={StaticResource StringToVisibilityConverter}}" />
Where StringToVisibilityConverteris defined like this:
whereStringToVisibilityConverter是这样定义的：
[ValueConversion(typeof(string), typeof(Visibility))]
public class StringToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (string.IsNullOrEmpty((string)value))
{
return Visibility.Collapsed;
}
else
{
return Visibility.Visible;
}
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
回答by devdigital
You can use a DataTrigger:
您可以使用DataTrigger：
<TextBlock Text="{Binding Path=Title}">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding Title}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
