c# - 如果文本框不为空，如何添加和显示工具提示文本框 WPF

Question

需要显示一个提示，其中包含来自文本字段的数据。如果文本框有数据则提示出现。

Answer 1

只需使用绑定(bind)到 ToolTipService 附加属性。 XAML:

<UserControl.Resources>
    <converters:IsStringNonemptyConverter x:Key="ToolTipVisibilityConveter" />
</UserControl.Resources>

<TextBox Name="textBox" VerticalAlignment="Center" HorizontalAlignment="Center" Width="150"
         ToolTipService.ToolTip="{Binding Text, RelativeSource={RelativeSource Self}}"
         ToolTipService.IsEnabled="{Binding Text, RelativeSource={RelativeSource Self}, Converter={StaticResource ToolTipVisibilityConveter}}"/>

转换器:

internal sealed class IsStringNonemptyConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return !String.IsNullOrEmpty(value as string);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}