xaml - windows phone 8.1 ComboBox 当项目数量更多时，将多个项目显示为已选择

Question

当组合框中有更多项目时，组合框将显示列表选择器弹出窗口。如果我选择第一个并向下滚动，则会将多个项目显示为已选择。但是 ComboBox 的 SelectedItem 将是我选择的那个。我修改了ListPickerFlyout的样式，关闭了ListView的虚拟化。如果我这样做 ListView 不会保留 SelectedItem。这是 ComboBox 的错误吗？这个问题有没有解决办法

这是我修改的样式

 <DataTemplate x:Key="ListPickerFlyoutPresenterContentTemplate" >
                <ListView VirtualizingStackPanel.VirtualizationMode="Recycling" SelectionMode="Single"   > 
                    <!--<ListView.ItemsPanel>
                        <ItemsPanelTemplate>
                            <VirtualizingStackPanel/>
                        </ItemsPanelTemplate>
                    </ListView.ItemsPanel>-->
                    <ListView.ItemContainerStyle>

                           <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="ListViewItem">
                                        <Border x:Name="OuterContainer" RenderTransformOrigin="0.5,0.5">
                                            <VisualStateManager.VisualStateGroups>
                                                <VisualStateGroup x:Name="CommonStates">
                                                    <VisualState x:Name="Normal" />
                                                    <VisualState x:Name="Pressed"/>

                                                    <VisualState x:Name="Disabled"/>
                                                                                                                                                        <VisualStateGroup.Transitions>
                                                        <VisualTransition From="Pressed" To="Normal" />


                                                    </VisualStateGroup.Transitions>
                                                </VisualStateGroup>
                                                <VisualStateGroup x:Name="SelectionStates">
                                                    <VisualState x:Name="Unselected" />
                                                    <VisualState x:Name="Selected">
                                                        <Storyboard>
                                                            <DoubleAnimation Storyboard.TargetName="CheckGlyph" Storyboard.TargetProperty="Opacity" Duration="0" To="1" />
                                                            <DoubleAnimation Storyboard.TargetName="SelectedCheckMark" Storyboard.TargetProperty="Opacity" Duration="0" To="1" />
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="contentPresenter" Storyboard.TargetProperty="Foreground" Duration="0">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Green" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentBorder" Storyboard.TargetProperty="Background">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ListPickerFlyoutPresenterSelectedItemBackgroundThemeBrush}" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                        </Storyboard>
                                                    </VisualState>
                                                    <VisualState x:Name="SelectedUnfocused">
                                                        <Storyboard>
                                                            <DoubleAnimation Storyboard.TargetName="CheckGlyph" Storyboard.TargetProperty="Opacity" Duration="0" To="1" />
                                                            <DoubleAnimation Storyboard.TargetName="SelectedCheckMark" Storyboard.TargetProperty="Opacity" Duration="0" To="1" />
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="contentPresenter" Storyboard.TargetProperty="Foreground" Duration="0">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Green" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentBorder" Storyboard.TargetProperty="Background">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ListPickerFlyoutPresenterSelectedItemBackgroundThemeBrush}" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                        </Storyboard>
                                                    </VisualState>
                                                </VisualStateGroup>
                                                <VisualStateGroup x:Name="DataVirtualizationStates">
                                                    <VisualState x:Name="DataAvailable" />
                                                    <VisualState x:Name="DataPlaceholder">

                                                    </VisualState>
                                                </VisualStateGroup>
                                                <VisualStateGroup x:Name="MultiSelectStates">
                                                    <VisualState x:Name="NoMultiSelect" />
                                                    <VisualState x:Name="ListMultiSelect">

                                                    </VisualState>
                                                    <VisualState x:Name="GridMultiSelect" />
                                                    <VisualStateGroup.Transitions>
                                                        <VisualTransition From="ListMultiSelect" To="NoMultiSelect" GeneratedDuration="0:0:0.15" />
                                                        <VisualTransition From="NoMultiSelect" To="ListMultiSelect" GeneratedDuration="0:0:0.15" />
                                                    </VisualStateGroup.Transitions>
                                                </VisualStateGroup>
                                                <!--<VisualStateGroup x:Name="HighlightStates">
                                                    <VisualState x:Name="NoHighlight" />
                                                    <VisualState x:Name="Highlighted">
                                                        <Storyboard>
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="contentPresenter" Storyboard.TargetProperty="Foreground" Duration="0">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Red" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentBorder" Storyboard.TargetProperty="Background">
                                                                <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource ListPickerFlyoutPresenterSelectedItemBackgroundThemeBrush}" />
                                                            </ObjectAnimationUsingKeyFrames>
                                                        </Storyboard>
                                                    </VisualState>
                                                </VisualStateGroup>-->
                                            </VisualStateManager.VisualStateGroups>

                                                            <Grid>
                                                                <ContentPresenter x:Name="contentPresenter"
                                        ContentTransitions="{TemplateBinding ContentTransitions}"
                                        ContentTemplate="{TemplateBinding ContentTemplate}"
                                        Content="{TemplateBinding Content}"
                                        HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                        VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                                        Margin="{TemplateBinding Padding}"
                                        Style="{ThemeResource FlyoutPickerListViewItemContentPresenterStyle}" />
                                                                 <!--The 'Xg' text simulates the amount of space one line of text will occupy.
                                            In the DataPlaceholder state, the Content is not loaded yet so we
                                            approximate the size of the item using placeholder text.--> 
                                                                <TextBlock x:Name="PlaceholderTextBlock"
                                 Opacity="0"
                                 Text="Xg"
                                 Foreground="{x:Null}"
                                 Margin="{TemplateBinding Padding}"
                                 IsHitTestVisible="False"
                                 AutomationProperties.AccessibilityView="Raw"/>
                                                                <Rectangle x:Name="PlaceholderRect"
                                 Visibility="Collapsed"
                                 Fill="{ThemeResource FlyoutBackgroundThemeBrush}"
                                 IsHitTestVisible="False" />
                                                            </Grid>
                                                        </Border>
                                                    </Border>
                                                </Border>
                                                <Border x:Name="SelectedBorder"
                      IsHitTestVisible="False"
                      Opacity="0"
                      BorderBrush="{ThemeResource ListViewItemSelectedBackgroundThemeBrush}"
                      BorderThickness="{ThemeResource GridViewItemMultiselectBorderThickness}">
                                                    <Grid x:Name="SelectedCheckMark"
                      Opacity="0"
                      Height="34"
                      Width="34"
                      HorizontalAlignment="Right"
                      VerticalAlignment="Top">
                                                        <Path x:Name="SelectedEarmark" Data="M0,0 L40,0 L40,40 z"
                        Fill="{ThemeResource ListViewItemSelectedBackgroundThemeBrush}"
                        Stretch="Fill" />
                                                        <Path x:Name="SelectedGlyph"
                        Data="M0,123 L39,93 L124,164 L256,18 L295,49 L124,240 z"
                        Fill="{ThemeResource ListViewItemCheckThemeBrush}"
                        Height="14.5"
                        Stretch="Fill"
                        Width="17"
                        HorizontalAlignment="Right"
                        Margin="0,1,1,0"
                        VerticalAlignment="Top"
                        FlowDirection="LeftToRight" />
                                                    </Grid>
                                                </Border>
                                            </Grid>
                                        </Border>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>

                    </ListView.ItemContainerStyle>
                    <ListView.Footer>
                        <Border Height="{ThemeResource ListPickerFlyoutFooterThemeHeight}" Width="1" />
                    </ListView.Footer>                     
                </ListView>
            </DataTemplate>

当我选择某个项目时，它不会进入选定的视觉状态，它实际上进入突出显示的视觉状态，当我关闭虚拟化时，不会保留之前的突出显示状态

Answer 1

问题在于 listviewitems 的虚拟化(它是控件中的一个错误)。

解决这个问题的方法是设置 CacheLength ListView 的 itemsstackpanel 的属性。

代码是:

<DataTemplate x:Key="ListPickerFlyoutPresenterContentTemplate">
    <ListView ItemContainerStyle="{StaticResource ListPickerFlyoutPresenterItemStyle}">
       <ListView.ItemsPanel>
           <ItemsPanelTemplate>
                <ItemsStackPanel  CacheLength="10" />
            </ItemsPanelTemplate>
        </ListView.ItemsPanel>

        <ListView.Footer>
            <Border Height="{ThemeResource ListPickerFlyoutFooterThemeHeight}"
                    Width="1" />
        </ListView.Footer>
    </ListView>
</DataTemplate>

该解决方案仅在项目实现后的一段时间(几秒钟)后删除选择突出显示。

希望解决方案没问题，否则您将不得不覆盖 PrepareContainerForItemOverride ListView 的