c++ - 如何防止 XAML UI 元素在失去焦点时修改其外观

Question

我正在尝试开发一个 Windows 应用商店应用程序，想知道是否有一种方法可以防止 XAML UI 元素在失去焦点时在视觉上发生变化。例如，如果我有 RichEditBox 选择了一些文本然后按下按钮，可能以某种方式修改文本或在应用程序的其他地方做一些事情，RichEditBox 变暗(即背景颜色改变)并且所选文本是不再显示为突出显示。有没有办法防止这种情况发生？还是控制变化？

Answer 1

是的，这意味着为上述 <RichEditBox> 制作您自己的样式模板.其实很简单，放一个<RichEditBox>到 UI Designer，转到 Document Online 并提取模板。这将创建一个新的资源样式，您可以将其应用于任何 <RichEditBox> .因为你不想取消高亮，所以你必须像这样注释掉 Normal, PointerOver 的 VisualState

---

<Page.Resources>
    <Style x:Key="Chubs_RichEditBoxStyle" 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>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="*"/>
                        </Grid.RowDefinitions>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBackgroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBorderThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Normal">
                                    <Storyboard>
                                        <!--
                                        <DoubleAnimation Duration="0" To="{ThemeResource TextControlBackgroundThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement"/>
                                        <DoubleAnimation Duration="0" To="{ThemeResource TextControlBorderThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
                                        -->
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="PointerOver">
                                    <Storyboard>
                                        <!--
                                        <DoubleAnimation Duration="0" To="{ThemeResource TextControlPointerOverBackgroundThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement"/>
                                        <DoubleAnimation Duration="0" To="{ThemeResource TextControlPointerOverBorderThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
                                        -->
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Focused"/>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="BackgroundElement" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" Margin="{TemplateBinding BorderThickness}" Grid.Row="1" Grid.RowSpan="2"/>
                        <Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" Grid.Row="1" Grid.RowSpan="1"/>
                        <ContentPresenter x:Name="HeaderContentPresenter" Grid.ColumnSpan="2" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource TextBoxForegroundHeaderThemeBrush}" FontWeight="Semilight" Margin="0,4,0,4" Grid.Row="0"/>
                        <ScrollViewer x:Name="ContentElement" AutomationProperties.AccessibilityView="Raw" HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsTabStop="False" IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}" IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}" IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}" ZoomMode="Disabled"/>
                        <ContentControl x:Name="PlaceholderTextContentPresenter" Grid.ColumnSpan="2" Content="{TemplateBinding PlaceholderText}" Foreground="{ThemeResource TextBoxPlaceholderTextThemeBrush}" IsHitTestVisible="False" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Page.Resources>

---

现在将该样式应用于任何 <RichEditBox>

<RichEditBox Height="400" Style="{StaticResource Chubs_RichEditBoxStyle}" />

---

要使其不取消选择您的文本，您必须制作自己的自定义 RichEditBox，这非常简单。

namespace what_ever_your_namespace_is
{
    public class Chubs_RichTextBox : RichEditBox
    {
        protected override void OnLostFocus(RoutedEventArgs e)
        {
        }        
    }
}

然后将 namespace 添加到您的 XAML 中

<Page
    xmlns:CustomControls="using:what_ever_your_namespace_is"
>

然后使用上面样式的新控件

<CustomControls:Chubs_RichTextBox  Height="400" Style="{StaticResource Chubs_RichEditBoxStyle}" ></CustomControls:Chubs_RichTextBox>

干杯:D