WinUI默认样式中的条件XAML Setter在UWP中为何失效？

我从WinUI仓库复制了默认的Button样式到空UWP项目中，运行时出现错误：XAML二进制格式（XBF）生成器报告语法错误‘0x03e9’。移除<Style>内的条件Setter后项目可正常运行，但控件模板内的条件XAML能正常工作，请问哪里操作有误？

<Application
    x:Class="App1.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    
    xmlns:contract7Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)"
    xmlns:contract7NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,7)"
    xmlns:local="using:Microsoft.UI.Xaml.Controls">

    <Application.Resources>
        <Style x:Key="DefaultButtonStyle" TargetType="Button">
            <Setter Property="Background" Value="{ThemeResource ButtonBackground}" />
            <contract7Present:Setter Property="BackgroundSizing" Value="InnerBorderEdge" />
            <Setter Property="Foreground" Value="{ThemeResource ButtonForeground}" />
            <Setter Property="BorderBrush" Value="{ThemeResource ButtonBorderBrush}" />
            <Setter Property="BorderThickness" Value="{ThemeResource ButtonBorderThemeThickness}" />
            <contract7NotPresent:Setter Property="Padding" Value="11,5,11,5" />
            <contract7Present:Setter Property="Padding" Value="{StaticResource ButtonPadding}" />
            <Setter Property="HorizontalAlignment" Value="Left" />
            <Setter Property="VerticalAlignment" Value="Center" />
            <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
            <Setter Property="FontWeight" Value="Normal" />
            <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
            <Setter Property="UseSystemFocusVisuals" Value="{StaticResource UseSystemFocusVisuals}" />
            <Setter Property="FocusVisualMargin" Value="-3" />
            <contract7Present:Setter Property="CornerRadius" Value="{ThemeResource ControlCornerRadius}" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <ContentPresenter
                        x:Name="ContentPresenter"
                        Background="{TemplateBinding Background}"
                        contract7Present:BackgroundSizing="{TemplateBinding BackgroundSizing}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        Content="{TemplateBinding Content}"
                        ContentTemplate="{TemplateBinding ContentTemplate}"
                        ContentTransitions="{TemplateBinding ContentTransitions}"
                        contract7Present:CornerRadius="{TemplateBinding CornerRadius}"
                        contract7NotPresent:CornerRadius="{ThemeResource ControlCornerRadius}"
                        Padding="{TemplateBinding Padding}"
                        HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                        VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                        AutomationProperties.AccessibilityView="Raw"
                        local:AnimatedIcon.State="Normal">

                            <contract7Present:ContentPresenter.BackgroundTransition>
                                <contract7Present:BrushTransition Duration="0:0:0.083" />
                            </contract7Present:ContentPresenter.BackgroundTransition>

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

                                    <VisualState x:Name="PointerOver">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBackgroundPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBorderBrushPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonForegroundPointerOver}" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                        <VisualState.Setters>
                                            <Setter Target="ContentPresenter.(local:AnimatedIcon.State)" Value="PointerOver"/>
                                        </VisualState.Setters>
                                    </VisualState>

                                    <VisualState x:Name="Pressed">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBackgroundPressed}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBorderBrushPressed}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonForegroundPressed}" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                        <VisualState.Setters>
                                            <Setter Target="ContentPresenter.(local:AnimatedIcon.State)" Value="Pressed"/>
                                        </VisualState.Setters>
                                    </VisualState>

                                    <VisualState x:Name="Disabled">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Background">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBackgroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="BorderBrush">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonBorderBrushDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="Foreground">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ButtonForegroundDisabled}" />
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                        <VisualState.Setters>
                                            <!-- DisabledVisual Should be handled by the control, not the animated icon. -->
                                            <Setter Target="ContentPresenter.(local:AnimatedIcon.State)" Value="Normal"/>
                                        </VisualState.Setters>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                        </ContentPresenter>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Application.Resources>
</Application>

原因与解决方法 #

• UWP原生不支持样式级别的条件Setter：你用的contract7Present:Setter这类条件Setter是WinUI（Microsoft.UI.Xaml）专属语法，UWP的XBF生成器无法识别<Style>根节点下的这种条件Setter，仅支持在控件模板内部使用属性级的条件XAML（比如模板里的contract7Present:BackgroundSizing）。
• 可行的解决方式：
  1. 若项目允许，直接升级为WinUI 3项目，原生支持这类WinUI特有的样式语法。
  2. 针对纯UWP项目，调整样式写法：
     • 手动移除样式内的条件Setter，根据你的目标SDK版本，直接设置兼容的属性值；
     • 或者在代码后台，通过ApiInformation.IsApiContractPresent判断API契约版本，运行时给Button设置对应属性，规避XAML里的条件Setter语法。
  3. 基于UWP原生Button样式修改，不要直接复制WinUI的样式，两者的XAML语法支持范围有差异。

内容的提问来源于stack exchange，提问作者Mapplesoft