我想在UWP / Xamarin上配置工具栏，以使工具栏项目下方的标签始终可见（请参见：uwp commandbar always show label，底部图像）。
问题在于应用程序是用Xamarin Forms编写的，工具栏似乎是页面的组成部分，所以我想到的唯一解决方案是为页面编写某种自定义渲染器，然后尝试从那里访问命令栏。还是有更简单的解决方案？
答案 0 :(得分：0)
在UWP / Xamarin上始终可见的工具栏项目标签
您不需要自定义渲染器，而从source code派生。 ToolbarItem是uwp平台中带有AppBarButton的渲染器。因此，您可以在uwp App.Xaml文件中使用Justin XL提供的AppBarButton样式，要使样式成为全局样式，请删除x:key值，然后将AppBarThemeCompactHeight设置为60。以下代码是完成即可直接使用。
<Application.Resources>
<ResourceDictionary>
<x:Double x:Key="AppBarThemeCompactHeight">60</x:Double>
<Style TargetType="AppBarButton">
<Setter Property="Background" Value="{ThemeResource AppBarButtonBackground}" />
<Setter Property="Foreground" Value="{ThemeResource AppBarButtonForeground}" />
<Setter Property="BorderBrush" Value="{ThemeResource AppBarButtonBorderBrush}" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
<Setter Property="FontWeight" Value="Normal" />
<Setter Property="Width" Value="68" />
<Setter Property="UseSystemFocusVisuals" Value="True" />
<Setter Property="AllowFocusOnInteraction" Value="False" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="AppBarButton">
<Grid
x:Name="Root"
MinWidth="{TemplateBinding MinWidth}"
MaxWidth="{TemplateBinding MaxWidth}"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
>
<Grid.Resources>
<Style x:Name="LabelOnRightStyle" TargetType="AppBarButton">
<Setter Property="Width" Value="NaN" />
</Style>
</Grid.Resources>
<Grid x:Name="ContentRoot" MinHeight="{ThemeResource AppBarThemeMinHeight}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ContentPresenter
x:Name="Content"
Height="20"
Margin="0,14,0,4"
HorizontalAlignment="Stretch"
AutomationProperties.AccessibilityView="Raw"
Content="{TemplateBinding Icon}"
Foreground="{TemplateBinding Foreground}"
/>
<TextBlock
x:Name="TextLabel"
Grid.Row="1"
Margin="2,0,2,6"
FontFamily="{TemplateBinding FontFamily}"
FontSize="12"
Foreground="{TemplateBinding Foreground}"
Text="{TemplateBinding Label}"
TextAlignment="Center"
TextWrapping="Wrap"
/>
</Grid>
<TextBlock
x:Name="OverflowTextLabel"
Margin="12,0,12,0"
Padding="0,5,0,7"
HorizontalAlignment="Stretch"
VerticalAlignment="Center"
FontFamily="{TemplateBinding FontFamily}"
FontSize="15"
Foreground="{TemplateBinding Foreground}"
Text="{TemplateBinding Label}"
TextAlignment="Left"
TextTrimming="Clip"
TextWrapping="NoWrap"
Visibility="Collapsed"
/>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="ApplicationViewStates">
<VisualState x:Name="FullSize" />
<VisualState x:Name="Compact">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="LabelOnRight">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Content" Storyboard.TargetProperty="Margin">
<DiscreteObjectKeyFrame KeyTime="0" Value="12,14,0,14" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentRoot" Storyboard.TargetProperty="MinHeight">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarThemeCompactHeight}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="(Grid.Row)">
<DiscreteObjectKeyFrame KeyTime="0" Value="0" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="(Grid.Column)">
<DiscreteObjectKeyFrame KeyTime="0" Value="1" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="TextAlignment">
<DiscreteObjectKeyFrame KeyTime="0" Value="Left" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Margin">
<DiscreteObjectKeyFrame KeyTime="0" Value="8,15,12,17" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="LabelCollapsed">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentRoot" Storyboard.TargetProperty="MinHeight">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarThemeCompactHeight}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Overflow">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentRoot" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="OverflowWithToggleButtons">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentRoot" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Margin">
<DiscreteObjectKeyFrame KeyTime="0" Value="38,0,12,0" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal">
<Storyboard>
<PointerUpThemeAnimation Storyboard.TargetName="OverflowTextLabel" />
</Storyboard>
</VisualState>
<VisualState x:Name="PointerOver">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundPointerOver}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="BorderBrush">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushPointerOver}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Content" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}" />
</ObjectAnimationUsingKeyFrames>
<PointerUpThemeAnimation Storyboard.TargetName="OverflowTextLabel" />
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundPressed}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="BorderBrush">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushPressed}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Content" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}" />
</ObjectAnimationUsingKeyFrames>
<PointerDownThemeAnimation Storyboard.TargetName="OverflowTextLabel" />
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundDisabled}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Root" Storyboard.TargetProperty="BorderBrush">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushDisabled}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="Content" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="OverflowTextLabel" Storyboard.TargetProperty="Foreground">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="InputModeStates">
<VisualState x:Name="InputModeDefault" />
<VisualState x:Name="TouchInputMode">
<VisualState.Setters>
<Setter Target="OverflowTextLabel.Padding" Value="0,11,0,13" />
</VisualState.Setters>
</VisualState>
<VisualState x:Name="GameControllerInputMode">
<VisualState.Setters>
<Setter Target="OverflowTextLabel.Padding" Value="0,11,0,13" />
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
</Application.Resources>