WPF 工具提示仅在文本为某些内容时显示
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WPF Tooltip Show only when Text is something
提问by Walter Boss
i am having the following code:
我有以下代码：
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style x:Key="{x:Type ToolTip}" TargetType="{x:Type ToolTip}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToolTip}">
<Border Background="Black">
<TextBlock FontFamily="Tahoma" FontSize="11" Text="{TemplateBinding Content}" Foreground="WhiteSmoke" Padding="2" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<StackPanel>
<Label Content="Label 1" ToolTip="asd" />
<Label Content="Label 2" ToolTip="" />
<TextBlock Text="TextBlock 1" ToolTip="asd" />
<TextBlock Text="TextBlock 2" ToolTip="" />
<Button Content="Button 1" ToolTip="asd" />
<Button Content="Button 2" ToolTip="" />
</StackPanel>
Now, as you can see by testing that when you hover over Label 2, Textblock 2, Button 2, a tooltip still shows. I want that to be triggered that if Tooltip is empty or null then it should not show anything. I know i can simply remove that from XAML But the way i am doing here is something different.
现在，正如您通过测试看到的那样，当您将鼠标悬停在标签 2、文本块 2、按钮 2 上时，仍然会显示工具提示。我希望触发它，如果 Tooltip 为空或 null，那么它不应该显示任何内容。我知道我可以简单地从 XAML 中删除它但是我在这里做的方式有所不同。
I have tried adding a trigger to check value ="" and to null and inside trigger, setting template to null but none of them is working
我尝试添加一个触发器来检查值 ="" 和 null 和内部触发器，将模板设置为 null 但它们都不起作用
If some of you experts could shed some light on it, i would be very glad
如果你们中的一些专家可以对此有所了解，我会很高兴
回答by Metro Smurf
A converter is probably overkill when a DataTrigger can accomplish the same thing. The following style is your posted style, with a bit of clean up and the necessary triggers. Note the following:
当 DataTrigger 可以完成同样的事情时，转换器可能是矫枉过正的。以下样式是您发布的样式，有一些清理和必要的触发器。请注意以下事项：
- I typically set the default style that will eventually be overridden by a trigger. In this case, the default style is
Visibility=Visible. - There are two triggers. One for when the content is null and the other when the content is empty.
- 我通常会设置最终会被触发器覆盖的默认样式。在这种情况下，默认样式是
Visibility=Visible。 - 有两个触发器。一种用于内容为空时，另一种用于内容为空时。
XAML
XAML
<Style TargetType="ToolTip">
<Setter Property="Visibility" Value="Visible" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ToolTip">
<Border Background="Black">
<TextBlock FontFamily="Tahoma"
FontSize="11"
Foreground="WhiteSmoke"
Padding="2"
Text="{TemplateBinding Content}" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Content}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Content}" Value="">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
</Style.Triggers>
</Style>
回答by prthrokz
You can consider using a IValueConverter to show/hide the tooltip border. Add this class to your project :
您可以考虑使用 IValueConverter 来显示/隐藏工具提示边框。将此类添加到您的项目中：
class BorderVisibilitySetter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
//check if the control's content property is null or empty
if(value == null || value.ToString() == string.Empty)
return Visibility.Collapsed;
else
return Visibility.Visible;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
Then modify your xaml as :
然后将您的 xaml 修改为：
<src:BorderVisibilitySetter x:Key="BorderVisible" />
<Style x:Key="{x:Type ToolTip}" TargetType="{x:Type ToolTip}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToolTip}">
<Border Background="Black" Visibility="{TemplateBinding Content, Converter={StaticResource BorderVisible}}" >
<TextBlock FontFamily="Tahoma" FontSize="11" Text="{TemplateBinding Content}" Foreground="WhiteSmoke" Padding="2" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
回答by Palash Roy
My solution will have below features:
我的解决方案将具有以下功能：
- Tooltip will be displayed if textblock has some text
- Tooltip text is same as textblock text
- Tooltip foreground is same as textblock foreground
- 如果文本块有一些文本，将显示工具提示
- 工具提示文本与文本块文本相同
- 工具提示前景与文本块前景相同
Xaml Code:
Xml代码：
<TextBlock Name="TxtBlockLicenseInfo" Height="35" ToolTipService.ShowDuration="200000" TextTrimming="CharacterEllipsis">
<TextBlock.ToolTip>
<ToolTip DataContext="{Binding Path=PlacementTarget, RelativeSource={x:Static RelativeSource.Self}}"
Visibility="{Binding Text,Converter={StaticResource TextToTooltipVisibilityConverter}}" >
<StackPanel>
<Label Content="{Binding Text}" Foreground="{Binding Foreground}" >
</Label>
</StackPanel>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
Also include the converter in the Xaml resources
还将转换器包含在 Xaml 资源中
<UserControl.Resources>
<local:LicenseInformationToTooltipVisibilityConverter x:Key="LicenseInformationToTooltipVisibilityConverter" />
</UserControl.Resources>
Xaml.Cs Code to write the converter
Xaml.Cs 编写转换器的代码
public class TextToTooltipVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if ((value.ToString().Equals(string.Empty)))
{
return Visibility.Collapsed;
}
else return Visibility.Visible;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return Visibility.Visible;
}
}
