WPF自定义控件模板-相对字体大小 [英] Wpf custom control template - relative font size

问题描述

我正在创建一个自定义WPF控件，为了简单起见，它具有一个带有标题 TextBlock的垂直堆栈面板，后跟一个ContentPresenter。我希望标题的字体大小比内容中使用的大小大5点，这是由用户将控件放置在其中的任何容器继承的。

I am creating a custom WPF control that let's say for simplicity sake has a vertical stack panel with a "title" TextBlock, followed by a ContentPresenter. I want the font size for the "title" to be 5 Points LARGER than the size used in the content, which is inherited by whatever container the user places this control in.

如何在控件模板中使用相对值为标题元素指定字体大小，而又不向用户公开 TitleFontSize之类的属性？我想做加5。

How can I specify a font size in the control template for the header element using a relative value without exposing a property like "TitleFontSize" to the user? I want do "add 5".

我尝试在标头文本块上使用ScaleTransform混合结果（文本块可以缩放，但是方向已修改-我有文本右对齐，并且缩放后将其移出控件区域）。另外，我不确定比例转换是否在这里合适。

I tried using a ScaleTransform on the header text block with mixed results (the text block scaled fine but the orientation was modified - I had the text right-justified and it moved "off the control" area when scaled). Also, I am not sure if scale transform would be approprite here.

推荐答案

我使用IValueConverter进行了如下操作：

I did it with an IValueConverter as follows:

已创建从IValueConverter派生的FontSizeConverter类。 Convert方法的值加10，而ConvertBack方法的值减10。

Created a class FontSizeConverter that derives from IValueConverter. The Convert method adds 10 to the value, and the ConvertBack method subtracts 10.

public class FontSizeConverter : IValueConverter
{

    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (double)value + 12.0;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (double)value - 12.0;
    }

    #endregion
}

下一步，我在控件的XAML模板中声明了此类的实例：

Next, I declaried an instance of this class in the XAML template for the control:

<Style.Resources>
        <local:FontSizeConverter x:Key="fontSizeConverter"/>
</Style.Resources>

Finnaly，FontSize绑定使用此转换器应用于继承的FontSize属性：

And Finnaly, the FontSize binding uses this converter applied to the inherited FontSize property:

<TextBlock FontSize="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=FontSize, Converter={StaticResource fontSizeConverter}}" 
                                   Grid.Row="0" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, 
                                   Path=Date.Day}" HorizontalAlignment="Right" VerticalAlignment="Top" Padding="2" Margin="2" >
 </TextBlock>

这有效。但是我仍然不知道这是否是正确的答案。让我知道是否有更好的方法，或者是否合适。

This works. But I still do not know if this is the correct answer. Let me know if there is a better way, or if this is appropriate.

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