RichEditBox在禁用时松开颜色格式，然后启用

Question

我在UWP应用程序中使用RichEditBox，我需要在软件中启用和禁用它来执行一些任务。我遇到的问题是，当我禁用，然后重新启用它，任何颜色格式都会丢失。我在这里创造了一个简单的例子，来尝试这个问题。您可以键入一些文本，将其涂成红色，然后禁用并重新启用。颜色被还原成黑色。

XAML

<StackPanel>
    <StackPanel Orientation="Horizontal">
        <Button Content="Disable" Click="OnDisable"/>
        <Button Content="Enable" Click="OnEnable"/>
        <Button Content="Red" Click="OnRed"/>
    </StackPanel>
    <RichEditBox Name="RichEditor" Width="500" Height="200"/>
</StackPanel>

C#

private void OnDisable(object sender, RoutedEventArgs e)
{
    RichEditor.IsEnabled = false;
}

private void OnEnable(object sender, RoutedEventArgs e)
{
    RichEditor.IsEnabled = true;
}

private void OnRed(object sender, RoutedEventArgs e)
{
     RichEditor.Document.Selection.CharacterFormat.ForegroundColor = Colors.Red;
}

这看起来像RichEditBox组件中的一个bug，我想知道是否有人有办法让我在不丢失颜色格式的情况下启用和禁用文本。下面的例子可以重现这个问题。

Answer 1

请参阅控制样式和模板类中的RichEditBox部分：

您可以修改默认样式和ControlTemplate，使控件具有唯一的appearance.The默认样式、模板和定义控件外观的资源，这些都包含在generic.xaml文件中。出于设计目的，可以从(SDK)安装的(Program )\ Windows文件夹中获得generic.xaml。来自不同版本的SDK的样式和资源可能具有不同的值。

因此，您可以找到System.Windows.Controls.RichEditBox控件的默认样式，下面是1803版本的默认样式目标：

<!-- 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 TextControlForeground}" />
            <Setter Property="Background" Value="{ThemeResource TextControlBackground}" />
            <Setter Property="ContentLinkForegroundColor" Value="{ThemeResource ContentLinkForegroundColor}" />
            <Setter Property="ContentLinkBackgroundColor" Value="{ThemeResource ContentLinkBackgroundColor}" />
            <Setter Property="SelectionHighlightColor" Value="{ThemeResource TextControlSelectionHighlightColor}" />
            <Setter Property="BorderBrush" Value="{ThemeResource TextControlBorderBrush}" />
            <Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}" />
            <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
            <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
            <Setter Property="ScrollViewer.HorizontalScrollMode" Value="Auto" />
            <Setter Property="ScrollViewer.VerticalScrollMode" Value="Auto" />
            <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="UseSystemFocusVisuals" Value="{ThemeResource IsApplicationFocusVisualKindReveal}" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="RichEditBox">
                        <Grid>

                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">

                                    <VisualState x:Name="Disabled">

                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="HeaderContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlHeaderForegroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Normal" />

                                    <VisualState x:Name="PointerOver">

                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Focused">

                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundFocused}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundFocused}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushFocused}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundFocused}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="RequestedTheme">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Light" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>

                            </VisualStateManager.VisualStateGroups>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto" />
                                <RowDefinition Height="*" />
                            </Grid.RowDefinitions>
                            <Border x:Name="BorderElement"
                            Grid.Row="1"
                            Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Grid.ColumnSpan="2"
                            Grid.RowSpan="1" />
                            <ContentPresenter x:Name="HeaderContentPresenter"
                            x:DeferLoadStrategy="Lazy"
                            Visibility="Collapsed"
                            Grid.Row="0"
                            Foreground="{ThemeResource TextControlHeaderForeground}"
                            Margin="0,0,0,8"
                            Grid.ColumnSpan="2"
                            Content="{TemplateBinding Header}"
                            ContentTemplate="{TemplateBinding HeaderTemplate}"
                            FontWeight="Normal" />
                            <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" />
                            <TextBlock x:Name="PlaceholderTextContentPresenter"
                            Grid.Row="1"
                            Foreground="{ThemeResource TextControlPlaceholderForeground}"
                            Margin="{TemplateBinding BorderThickness}"
                            Padding="{TemplateBinding Padding}"
                            Grid.ColumnSpan="2"
                            Text="{TemplateBinding PlaceholderText}"
                            TextAlignment="{TemplateBinding TextAlignment}"
                            IsHitTestVisible="False" />

                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

从上面的样式中，您可以看到Disabled VisualState代码：

<VisualState x:Name="Disabled">

    <Storyboard>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="HeaderContentPresenter" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlHeaderForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>

在这个Disabled VisualState中，您可以发现当您禁用RichEditBox时，ContentElement的Foreground将是ThemeResource TextControlForegroundDisabled。由于在禁用RichEditBox时文本的Foreground已经更改，所以会丢失颜色格式。

可以通过删除将ContentElement的Foreground更改为禁用的VisualState的代码来保留颜色格式：

<VisualState x:Name="Disabled">

    <Storyboard>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="HeaderContentPresenter" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlHeaderForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushDisabled}" />
        </ObjectAnimationUsingKeyFrames>
        <!--<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>-->
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundDisabled}" />
        </ObjectAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>

Answer 2

Color myColor = Colors.Black; // this will act as your toggle of color you change it according to logic of your app in this case I will show you how you can retain the color even when disabled. Whenever you change the color of your richEditBox to red or to any color, just assign that color to it as well. Here I have set it default color to black.

private void OnDisable(object sender, RoutedEventArgs e)
{
    RichEditor.IsEnabled = false;
}

private void OnEnable(object sender, RoutedEventArgs e)
{
    RichEditor.IsEnabled = true;
    //Now after enabling just set the myColor property to RichEditBox Foreground.
    RichEditor.Document.Selection.CharacterFormat.ForegroundColor = myColor;
}

private void OnRed(object sender, RoutedEventArgs e)
{
     RichEditor.Document.Selection.CharacterFormat.ForegroundColor = Colors.Red;
     myColor = Colors.Red; // whatever color you set to the RichEditBox, set it to myColor as well.
}