如何在 UWP 中设置 ColorPickerSlider 元素、ColorChannel 属性？

Question

我不知道，如何在 c# 中动态设置 ColorPickerSlider 的 colorChannel 属性。我需要像我添加的图片一样的 ColorPickerSlider，基于从 colorSpectrum 中选择的颜色。我不想使用 ColorPicker 元素。我需要这个作为单独的组件。

ColorSpectrum ColorSpectrum = new ColorSpectrum();
ColorPickerSlider ColorPickerSlider = new ColorPickerSlider();
ColorPickerSlider.ColorChannel=???????;

Answer 1

在风格方面，我们可以考虑一种组合方式：

Rectangle + ColorPickerSlider

使用Rectangle作为背景，使用ColorPickerSlider作为实际的 function slider。

<Grid Width="300" Height="40">
    <Rectangle Height="15" VerticalAlignment="Center" Width="300" x:Name="BackgroundRect"/>
    <ColorPickerSlider ColorChannel="Hue" Style="{StaticResource ColorPickerSliderStyle}"/>
</Grid>

修改矩形背景颜色

var stopCollection = new GradientStopCollection();
stopCollection.Add(new GradientStop() { Color = Colors.Black, Offset=0 });
stopCollection.Add(new GradientStop() { Color = Colors.Purple, Offset=1 });
var brush = new LinearGradientBrush(stopCollection,0);
BackgroundRect.Fill = brush;

颜色选择器滑块样式

<Style x:Key="ColorPickerSliderStyle" TargetType="ColorPickerSlider">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Slider">
                <Grid>
                    <Grid.Resources>
                        <Style x:Key="SliderThumbStyle" TargetType="Thumb">
                            <Setter Property="BorderThickness" Value="0" />
                            <Setter Property="Background" Value="{ThemeResource ColorPickerSliderThumbBackground}" />
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="Thumb">
                                        <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="4" />
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Grid.Resources>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="*" />
                    </Grid.RowDefinitions>

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

                            <VisualState x:Name="Pressed">
                                <VisualState.Setters>
                                    <Setter Target="HorizontalThumb.Background" Value="{ThemeResource ColorPickerSliderThumbBackgroundPressed}" />
                                </VisualState.Setters>
                            </VisualState>

                            <VisualState x:Name="Disabled">
                                <VisualState.Setters>
                                    <Setter Target="HeaderContentPresenter.Foreground" Value="{ThemeResource SystemControlDisabledBaseMediumLowBrush}" />
                                    <Setter Target="HorizontalThumb.Background" Value="{ThemeResource ColorPickerSliderThumbBackgroundDisabled}" />
                                    <Setter Target="HorizontalTrackRect.Fill" Value="{ThemeResource ColorPickerSliderTrackFillDisabled}" />
                                    <Setter Target="HorizontalDecreaseRect.Fill" Value="{ThemeResource ColorPickerSliderTrackFillDisabled}" />
                                </VisualState.Setters>
                            </VisualState>

                            <VisualState x:Name="PointerOver">
                                <VisualState.Setters>
                                    <Setter Target="HorizontalThumb.Background" Value="{ThemeResource ColorPickerSliderThumbBackgroundPointerOver}" />
                                </VisualState.Setters>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="FocusEngagementStates">
                            <VisualState x:Name="FocusDisengaged" />
                            <VisualState x:Name="FocusEngagedHorizontal">
                                <VisualState.Setters>
                                    <Setter Target="SliderContainer.(Control.IsTemplateFocusTarget)" Value="False" />
                                    <Setter Target="HorizontalThumb.(Control.IsTemplateFocusTarget)" Value="True" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="FocusEngagedVertical">
                                <VisualState.Setters>
                                    <Setter Target="SliderContainer.(Control.IsTemplateFocusTarget)" Value="False" />
                                    <Setter Target="VerticalThumb.(Control.IsTemplateFocusTarget)" Value="True" />
                                </VisualState.Setters>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <ContentPresenter x:Name="HeaderContentPresenter" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource SliderHeaderForeground}" FontWeight="{ThemeResource SliderHeaderThemeFontWeight}" Margin="{ThemeResource SliderHeaderThemeMargin}" TextWrapping="Wrap" Visibility="Collapsed" x:DeferLoadStrategy="Lazy" />
                    <Grid x:Name="SliderContainer" Background="Transparent" Control.IsTemplateFocusTarget="True" Grid.Row="1">
                        <Grid x:Name="HorizontalTemplate" MinHeight="44">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto" />
                                <ColumnDefinition Width="Auto" />
                                <ColumnDefinition />
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="18" />
                                <RowDefinition Height="Auto" />
                                <RowDefinition Height="18" />
                            </Grid.RowDefinitions>
                            <Rectangle x:Name="HorizontalTrackRect" Grid.ColumnSpan="3" Fill="Transparent" Height="{ThemeResource SliderTrackThemeHeight}" Grid.Row="1" Opacity="0" />
                            <Rectangle x:Name="HorizontalDecreaseRect" Fill="Transparent" Grid.Row="1" Opacity="0" />
                            <Thumb x:Name="HorizontalThumb" AutomationProperties.AccessibilityView="Raw" Grid.Column="1" DataContext="{TemplateBinding Value}" Height="24" Grid.Row="0" Grid.RowSpan="3" Style="{StaticResource SliderThumbStyle}" Width="8">
                                <ToolTipService.ToolTip>
                                    <ToolTip x:Name="ToolTip" VerticalOffset="20" />
                                </ToolTipService.ToolTip>
                            </Thumb>
                        </Grid>
                    </Grid>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

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更新

关于计算渐变色

我们有两个 colors：黑色和紫色：

黑色（RGB）：0 0 0

紫色 (RGB)：128 0 128

我们假设ColorPickerSlider的Thumb在中间，取值为50（Slider最大值为100）

所以我们可以得到中间颜色为 (RGB) 64 0 64