当ListViewItem获得焦点时，如何使用VisualStateManager在ListViewItem中设置一个可见的元素

Question

在我的UWP中，我正在尝试创建一个ListView，它的DataTemplate将包含一个TextBox和一个不可见的AppBarButton。我想要做的是，当TextBox获得焦点或单击项目时，AppBarButton将设置为Visible。所以我创建了一个ControlTemplate，它包含一个VisualStateManager和AppBarButton，并将它设置为我的ListView的DataTemplate。

ControlTemplate：

    <ControlTemplate x:Key="TelephoneTemplate" TargetType="ListViewItem">
                <StackPanel Orientation="Vertical" >
                    <AppBarButton x:Name="DeleteIcon"  Icon="Cancel" HorizontalAlignment="Right" Foreground="{StaticResource TextGreyBrush}" Height="40" Width="40" Margin="0 0 -12  0"  Command="{Binding ElementName=ClientOverviewView, Path=DataContext.ClientDetailsViewModel.RemoveTelephoneCommand}" CommandParameter="{Binding}">
                        <AppBarButton.RenderTransform>
                            <CompositeTransform ScaleX="0.8" ScaleY="0.8"/>
                        </AppBarButton.RenderTransform>
                    </AppBarButton>
                    <ContentPresenter Content="{TemplateBinding Content}" />
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="DeleteIcon" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        <VisualState x:Name="Pressed">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="DeleteIcon" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="SelectionStates">
                            <VisualState x:Name="Selected">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="DeleteIcon" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>

                        </VisualStateGroup>
                        <VisualStateGroup x:Name="FocusStates">
                            <VisualState x:Name="Focused">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="DeleteIcon" Storyboard.TargetProperty="Visibility">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>

                    </VisualStateManager.VisualStateGroups>
                </StackPanel>
            </ControlTemplate>

ListView：

<ListView Grid.Row="2"   ItemsSource="{Binding ClientDetailsViewModel.ClientDetailsModel.Telephones}"  SelectionMode="None"  Margin="-10 4 -10 0" IsItemClickEnabled="True" >
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <ListViewItem Template="{StaticResource TelephoneTemplate}">
                                <ListViewItem.Content>
                                    <TextBox
                                            PlaceholderText="Telefon (erforderlich)"
                                            InputScope="TelephoneNumber"
                                            BorderThickness="1"
                                            BorderBrush="{StaticResource TextGreyBrush}"
                                            Foreground="{StaticResource TextGreyBrush}"
                                            Text="{Binding ContactText, Mode=TwoWay}" >

                                    </TextBox>
                                </ListViewItem.Content>
                            </ListViewItem>
                        </DataTemplate>
                    </ListView.ItemTemplate>

VisualState“Normal”似乎有效，因为当我将其值设置为“Collapsed”时，AppBarButton是不可见的。但是当我点击ListViewItem时，AppBarButton的可见性仍然是不可见的。我试过许多可见的状态，但它不起作用。