设置组合框的下拉高度(winrt)

我试图在xaml中设置一个combox框的下拉高度。我做的似乎都不管用。我正在构建下面的样式模板。

如有任何帮助，不胜感激。

<Style x:Key="ComboBoxStyle1" TargetType="ComboBox">
    <Setter Property="Padding" Value="8,0"/>
    <Setter Property="Foreground" Value="{StaticResource ComboBoxForegroundThemeBrush}"/>
    <Setter Property="Background" Value="{StaticResource ComboBoxBackgroundThemeBrush}"/>
    <Setter Property="BorderBrush" Value="{StaticResource ComboBoxBorderThemeBrush}"/>
    <Setter Property="BorderThickness" Value="{StaticResource ComboBoxBorderThemeThickness}"/>
    <Setter Property="TabNavigation" Value="Once"/>
    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>
    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
    <Setter Property="ScrollViewer.HorizontalScrollMode" Value="Disabled"/>
    <Setter Property="ScrollViewer.VerticalScrollMode" Value="Auto"/>
    <Setter Property="ScrollViewer.IsVerticalRailEnabled" Value="True"/>
    <Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="False"/>
    <Setter Property="ScrollViewer.BringIntoViewOnFocusChange" Value="True"/>
    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
    <Setter Property="FontFamily" Value="{StaticResource ContentControlThemeFontFamily}"/>
    <Setter Property="FontSize" Value="{StaticResource ControlContentThemeFontSize}"/>
    <Setter Property="ItemsPanel">
        <Setter.Value>
            <ItemsPanelTemplate>
                <CarouselPanel />
            </ItemsPanelTemplate>
        </Setter.Value>
    </Setter>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="ComboBox">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*"/>
                        <ColumnDefinition Width="32"/>
                    </Grid.ColumnDefinitions>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal"/>
                            <VisualState x:Name="PointerOver">
                                <Storyboard>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Pressed">
                            </VisualState>
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Background">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="Background">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxDisabledBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentPresenter">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="DropDownGlyph">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxArrowDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="FocusStates">
                            <VisualState x:Name="Focused">
                                <Storyboard>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="HighlightBackground"/>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="Highlight"/>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentPresenter">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxFocusedForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="FocusedPressed">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentPresenter">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ComboBoxPressedForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Unfocused"/>
                            <VisualState x:Name="PointerFocused"/>
                            <VisualState x:Name="FocusedDropDown">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Duration="0" Storyboard.TargetProperty="Visibility" Storyboard.TargetName="PopupBorder">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="DropDownStates">
                            <VisualState x:Name="Opened">
                                <Storyboard>
                                    <SplitOpenThemeAnimation ClosedTargetName="ContentPresenter" ContentTranslationOffset="0" ContentTargetName="ScrollViewer" ClosedLength="{Binding TemplateSettings.DropDownClosedHeight, RelativeSource={RelativeSource Mode=TemplatedParent}}" OffsetFromCenter="{Binding TemplateSettings.DropDownOffset, RelativeSource={RelativeSource Mode=TemplatedParent}}" OpenedTargetName="PopupBorder" OpenedLength="{Binding TemplateSettings.DropDownOpenedHeight, RelativeSource={RelativeSource Mode=TemplatedParent}}"/>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Closed">
                                <Storyboard>
                                    <SplitCloseThemeAnimation ClosedTargetName="ContentPresenter" ContentTranslationOffset="40" ContentTranslationDirection="{Binding TemplateSettings.SelectedItemDirection, RelativeSource={RelativeSource Mode=TemplatedParent}}" ContentTargetName="ScrollViewer" ClosedLength="{Binding TemplateSettings.DropDownClosedHeight, RelativeSource={RelativeSource Mode=TemplatedParent}}" OffsetFromCenter="{Binding TemplateSettings.DropDownOffset, RelativeSource={RelativeSource Mode=TemplatedParent}}" OpenedTargetName="PopupBorder" OpenedLength="{Binding TemplateSettings.DropDownOpenedHeight, RelativeSource={RelativeSource Mode=TemplatedParent}}"/>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Border x:Name="Background" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2"/>
                    <Rectangle x:Name="PressedBackground" Fill="{StaticResource ComboBoxPressedHighlightThemeBrush}" Margin="{TemplateBinding BorderThickness}" Opacity="0"/>
                    <Border x:Name="HighlightBackground" BorderBrush="{StaticResource ComboBoxFocusedBorderThemeBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{StaticResource ComboBoxFocusedBackgroundThemeBrush}" Grid.ColumnSpan="2" Opacity="0"/>
                    <Rectangle x:Name="Highlight" Fill="{StaticResource ComboBoxSelectedBackgroundThemeBrush}" Margin="{TemplateBinding BorderThickness}" Opacity="0"/>
                    <ContentPresenter x:Name="ContentPresenter" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    <TextBlock x:Name="DropDownGlyph" Grid.Column="1" Foreground="{StaticResource ComboBoxArrowForegroundThemeBrush}" FontWeight="Bold" FontSize="{StaticResource ComboBoxArrowThemeFontSize}" FontFamily="{StaticResource SymbolThemeFontFamily}" HorizontalAlignment="Right" IsHitTestVisible="False" Margin="0,0,6,4" Text="&#xE011;" VerticalAlignment="Center"/>
                    <Popup x:Name="Popup" Margin="0 10 0 0" >
                        <Border x:Name="PopupBorder" BorderBrush="{StaticResource ComboBoxPopupBorderThemeBrush}" BorderThickness="{StaticResource ComboBoxPopupBorderThemeThickness}" HorizontalAlignment="Stretch" Background="{StaticResource ComboBoxPopupBackgroundThemeBrush}" >
                            <ScrollViewer FontSize="16" x:Name="ScrollViewer" BringIntoViewOnFocusChange="{TemplateBinding ScrollViewer.BringIntoViewOnFocusChange}" 
                                          Foreground="{StaticResource ComboBoxPopupForegroundThemeBrush}" HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}" IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}" IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}" VerticalSnapPointsType="OptionalSingle" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" 
                                          VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}" HorizontalAlignment="Stretch" VerticalSnapPointsAlignment="Near" ZoomMode="Disabled">
                                <ItemsPresenter />
                            </ScrollViewer>
                        </Border>
                    </Popup>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>