在 C# WinRT 应用程序中填充 RichEditBox 的内容

Question

我正在尝试在 XAML/C# WinRT 应用程序中将填充应用到 RichEditBox 的顶部和底部，但它没有产生预期的效果。

基本上，当我将填充设置到这些边缘时，即使滚动控件的内容，填充也会产生空白空间。但是，我希望它填充 RichEditBox 的 content，这样当内容从顶部和底部边缘滚动时就没有可见的空白空间。

我该怎么做？

Answer 1

您正在寻找的是正在绘制的内容中的Margin，因为您希望所绘制的内容实际放大，而不是距离边缘一定距离的内容。

要添加此Margin，您需要编辑在样式中设置的模板。 The default style and template for the rich edit box is this：

<!-- Default style for System.Windows.Controls.RichEditBox -->
<Style TargetType="RichEditBox">
    <Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}" />
    <Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}" />
    <Setter Property="Foreground" Value="{ThemeResource TextBoxForegroundThemeBrush}" />
    <Setter Property="Background" Value="{ThemeResource TextBoxBackgroundThemeBrush}" />
    <Setter Property="SelectionHighlightColor" Value="{ThemeResource TextSelectionHighlightColorThemeBrush}" />
    <Setter Property="BorderBrush" Value="{ThemeResource TextBoxBorderThemeBrush}" />
    <Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}" />
    <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
    <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
    <Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="False" />
    <Setter Property="TextWrapping" Value="Wrap" />
    <Setter Property="Padding" Value="{ThemeResource TextControlThemePadding}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="RichEditBox">
                <Grid>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BackgroundElement"
                                                                   Storyboard.TargetProperty="Background">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBackgroundThemeBrush}" />
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement"
                                                                   Storyboard.TargetProperty="BorderBrush">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBorderThemeBrush}" />
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement"
                                                                   Storyboard.TargetProperty="Foreground">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}" />
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter"
                                                                   Storyboard.TargetProperty="Foreground">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}" />
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Normal">
                                <Storyboard>
                                    <DoubleAnimation Storyboard.TargetName="BackgroundElement"
                                                     Storyboard.TargetProperty="Opacity"
                                                     Duration="0"
                                                     To="{ThemeResource TextControlBackgroundThemeOpacity}" />
                                    <DoubleAnimation Storyboard.TargetName="BorderElement"
                                                     Storyboard.TargetProperty="Opacity"
                                                     Duration="0"
                                                     To="{ThemeResource TextControlBorderThemeOpacity}" />
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="PointerOver">
                                <Storyboard>
                                    <DoubleAnimation Storyboard.TargetName="BackgroundElement"
                                                     Storyboard.TargetProperty="Opacity"
                                                     Duration="0"
                                                     To="{ThemeResource TextControlPointerOverBackgroundThemeOpacity}" />
                                    <DoubleAnimation Storyboard.TargetName="BorderElement"
                                                     Storyboard.TargetProperty="Opacity"
                                                     Duration="0"
                                                     To="{ThemeResource TextControlPointerOverBorderThemeOpacity}" />
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Focused" />
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition Height="*"/>
                    </Grid.RowDefinitions>
                    <Border x:Name="BackgroundElement"
                            Grid.Row="1"
                            Background="{TemplateBinding Background}"
                            Margin="{TemplateBinding BorderThickness}"
                            Grid.ColumnSpan="2"
                            Grid.RowSpan="2"/>
                    <Border x:Name="BorderElement"
                            Grid.Row="1"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Grid.ColumnSpan="2"
                            Grid.RowSpan="1"/>
                    <ContentPresenter x:Name="HeaderContentPresenter"
                                      Grid.Row="0"
                                      Foreground="{ThemeResource TextBoxForegroundHeaderThemeBrush}"
                                      Margin="0,4,0,4"
                                      Grid.ColumnSpan="2"
                                      Content="{TemplateBinding Header}"
                                      ContentTemplate="{TemplateBinding HeaderTemplate}"
                                      FontWeight="Semilight" />
                    <ScrollViewer x:Name="ContentElement"
                                  Grid.Row="1"
                                  HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}"
                                  HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
                                  VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}"
                                  VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
                                  IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}"
                                  IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}"
                                  IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}"
                                  Margin="{TemplateBinding BorderThickness}"
                                  Padding="{TemplateBinding Padding}"
                                  IsTabStop="False"
                                  ZoomMode="Disabled" 
                                  AutomationProperties.AccessibilityView="Raw"/>
                    <ContentControl x:Name="PlaceholderTextContentPresenter"
                                  Grid.Row="1"
                                  Foreground="{ThemeResource TextBoxPlaceholderTextThemeBrush}"
                                  Margin="{TemplateBinding BorderThickness}"
                                  Padding="{TemplateBinding Padding}"
                                  IsTabStop="False"
                                  Grid.ColumnSpan="2"
                                  Content="{TemplateBinding PlaceholderText}" 
                                  IsHitTestVisible="False"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

注意ScrollViewer 直接应用Padding。不幸的是，这不是你想要的。如果您将其替换为 ContentPresenter，将 Padding 作为 TemplateBinding 应用到其 Margin，它应该按照您的意愿呈现。

<ScrollViewer 
  Grid.Row="1"
  HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}"
  HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
  VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}"
  VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
  IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}"
  IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}"
  IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}"
  Margin="{TemplateBinding BorderThickness}"
  IsTabStop="False"
  ZoomMode="Disabled" 
  AutomationProperties.AccessibilityView="Raw">
      <ContentPresenter x:Name="ContentElement" Margin="{TemplateBinding Padding}"/>
</ScrollViewer>

请注意，您必须将ContentPresenter 的Name 设置为ContentElement，以便控制逻辑知道它。

希望这对编码有所帮助！