如何防止 XAML UI 元素在失去焦点时修改其外观

How do I prevent a XAML UI element from modifying it's appearance on loss of focus

本文关键字：焦点 修改 外观 失去 何防止 XAML UI 元素      更新时间：2023-10-16

我正在尝试开发一个windows商店应用程序，并想知道是否有一种方法可以防止XAML UI元素在焦点丢失时发生视觉更改。例如，如果我选择了某个文本的RichEditBox，然后按下一个按钮，也许是为了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就会变暗（即背景颜色发生变化），并且所选文本不再显示为高亮显示。有没有办法防止这种情况发生？还是控制变化？

是的，这意味着为所述<RichEditBox>制作自己的样式模板。实际上，将<RichEditBox>放在UI设计器上，转到Document Online并提取模板非常简单。这将创建一个新的资源样式，您可以将其应用于任何<RichEditBox>。由于你不想去高亮，你必须注释掉VisualState for Normal，PointerOver，就像一样

<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}" />

为了让它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)
        {
        }        
    }
}

然后将名称空间添加到XAML 中

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

然后使用以上样式的新控件

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

干杯：D

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