XAML-附加到ListView的MenuFlyUtiItem不'；不能在WP8.1中工作

我开发了一个使用MVVM Lght工具包的通用应用程序

在一个页面上，我显示了一个评论列表。我想，用户可以添加一个新的评论，并编辑或删除其现有的评论

为了添加新评论，我在命令栏上使用了一个AppBarButton，效果很好

要编辑和删除现有评论，我想显示一个菜单，其中提供两项：“edit”和“delete”。我可以显示菜单，但当我点击它的项目时，什么都不会发生

这是我关心的xaml代码：

    <ListView x:Name="myCommentaires" 
              ItemsSource="{Binding Comments}"
              IsItemClickEnabled="True"
              SelectionMode="Single"
              SelectedItem="{Binding SelectedComment}"
              ContinuumNavigationTransitionInfo.ExitElementContainer="True">
        <ListView.ItemTemplate>
            <DataTemplate>
                <StackPanel Margin="0,0,19,12"
                            HorizontalAlignment="Stretch">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*" />
                            <ColumnDefinition Width="*" />
                        </Grid.ColumnDefinitions>
                        <!-- 1. Author -->
                        <TextBlock Grid.Column="0"
                                   Text="{Binding name}"
                                   HorizontalAlignment="Stretch" VerticalAlignment="Center"
                                   TextAlignment="Left"
                                   Margin="0" 
                                   Foreground="{StaticResource ThemeBrush}"
                                   Style="{StaticResource ListViewItemSubheaderTextBlockStyle}" />
                        <!-- 2. Date -->
                        <TextBlock Grid.Column="1"
                                   Text="{Binding date, Converter={StaticResource DateToStringConverter}}"
                                   HorizontalAlignment="Stretch" VerticalAlignment="Center"
                                   TextAlignment="Right"
                                   Margin="0" 
                                   Foreground="{StaticResource ThemeBrush}"
                                   Style="{StaticResource ListViewItemSubheaderTextBlockStyle}" />
                    </Grid>
                    <!-- 3. Content -->
                    <TextBlock Text="{Binding content}"
                               TextAlignment="Left"
                               TextWrapping="Wrap"
                               Margin="0" 
                               Foreground="Black"
                               FontSize="20"
                               Style="{StaticResource GroupHeaderTextBlockStyle}" />
                    <!-- MenuFlyout - with Commands -->
                    <FlyoutBase.AttachedFlyout>
                        <MenuFlyout>
                            <MenuFlyout.MenuFlyoutPresenterStyle>
                                <Style TargetType="MenuFlyoutPresenter">
                                    <Setter Property="Background" Value="{StaticResource ThemeBrush}"/>
                                </Style>
                            </MenuFlyout.MenuFlyoutPresenterStyle>
                            <MenuFlyoutItem Text="Edit"
                                            Command="{Binding EditCommentCommand}"/>
                            <MenuFlyoutItem Text="Delete" 
                                            Command="{Binding DeleteCommentCommand}"/>
                        </MenuFlyout>
                    </FlyoutBase.AttachedFlyout>
                    <!-- Behavior -->
                    <i:Interaction.Behaviors>
                        <core:EventTriggerBehavior EventName="Tapped">
                            <local:OpenFlyoutAction />
                        </core:EventTriggerBehavior>
                    </i:Interaction.Behaviors>
                </StackPanel>
            </DataTemplate>
        </ListView.ItemTemplate>
        <ListView.ItemContainerStyle>
            <Style TargetType="ListViewItem">
                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            </Style>
        </ListView.ItemContainerStyle>
    </ListView>

    // RelaydCommands declarations
    ...
    public RelayCommand AddCommentCommand { get; set; }
    public RelayCommand EditCommentCommand { get; set; }
    public RelayCommand DeleteCommentCommand { get; set; }
    ...

    // RelayCommands are affected in the constructor
    ...
    AddCommentaireCommand = new RelayCommand(AddCommentaire);
    EditCommentaireCommand = new RelayCommand(EditCommentaire);
    DeleteCommentaireCommand = new RelayCommand(DeleteCommentaire);
    ...

    // Methods related to the RelayCommands
    private async void AddComment()
    {
        NavigationService.NavigateTo<EditCommentViewModel>(this, new object[] { _article, _titleStructure.Title }, true); 
    }

    private async void EditComment()
    {
        NavigationService.NavigateTo<EditCommentViewModel>(this, new object[] { _article, _titleStructure.Title, SelectedComment }, true);
    }

    private async void DeleteComment()
    {
        var test = SelectedComment;
    }

这是我的视图模型代码：

    <ListView x:Name="myCommentaires" 
              ItemsSource="{Binding Comments}"
              IsItemClickEnabled="True"
              SelectionMode="Single"
              SelectedItem="{Binding SelectedComment}"
              ContinuumNavigationTransitionInfo.ExitElementContainer="True">
        <ListView.ItemTemplate>
            <DataTemplate>
                <StackPanel Margin="0,0,19,12"
                            HorizontalAlignment="Stretch">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*" />
                            <ColumnDefinition Width="*" />
                        </Grid.ColumnDefinitions>
                        <!-- 1. Author -->
                        <TextBlock Grid.Column="0"
                                   Text="{Binding name}"
                                   HorizontalAlignment="Stretch" VerticalAlignment="Center"
                                   TextAlignment="Left"
                                   Margin="0" 
                                   Foreground="{StaticResource ThemeBrush}"
                                   Style="{StaticResource ListViewItemSubheaderTextBlockStyle}" />
                        <!-- 2. Date -->
                        <TextBlock Grid.Column="1"
                                   Text="{Binding date, Converter={StaticResource DateToStringConverter}}"
                                   HorizontalAlignment="Stretch" VerticalAlignment="Center"
                                   TextAlignment="Right"
                                   Margin="0" 
                                   Foreground="{StaticResource ThemeBrush}"
                                   Style="{StaticResource ListViewItemSubheaderTextBlockStyle}" />
                    </Grid>
                    <!-- 3. Content -->
                    <TextBlock Text="{Binding content}"
                               TextAlignment="Left"
                               TextWrapping="Wrap"
                               Margin="0" 
                               Foreground="Black"
                               FontSize="20"
                               Style="{StaticResource GroupHeaderTextBlockStyle}" />
                    <!-- MenuFlyout - with Commands -->
                    <FlyoutBase.AttachedFlyout>
                        <MenuFlyout>
                            <MenuFlyout.MenuFlyoutPresenterStyle>
                                <Style TargetType="MenuFlyoutPresenter">
                                    <Setter Property="Background" Value="{StaticResource ThemeBrush}"/>
                                </Style>
                            </MenuFlyout.MenuFlyoutPresenterStyle>
                            <MenuFlyoutItem Text="Edit"
                                            Command="{Binding EditCommentCommand}"/>
                            <MenuFlyoutItem Text="Delete" 
                                            Command="{Binding DeleteCommentCommand}"/>
                        </MenuFlyout>
                    </FlyoutBase.AttachedFlyout>
                    <!-- Behavior -->
                    <i:Interaction.Behaviors>
                        <core:EventTriggerBehavior EventName="Tapped">
                            <local:OpenFlyoutAction />
                        </core:EventTriggerBehavior>
                    </i:Interaction.Behaviors>
                </StackPanel>
            </DataTemplate>
        </ListView.ItemTemplate>
        <ListView.ItemContainerStyle>
            <Style TargetType="ListViewItem">
                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            </Style>
        </ListView.ItemContainerStyle>
    </ListView>

    // RelaydCommands declarations
    ...
    public RelayCommand AddCommentCommand { get; set; }
    public RelayCommand EditCommentCommand { get; set; }
    public RelayCommand DeleteCommentCommand { get; set; }
    ...

    // RelayCommands are affected in the constructor
    ...
    AddCommentaireCommand = new RelayCommand(AddCommentaire);
    EditCommentaireCommand = new RelayCommand(EditCommentaire);
    DeleteCommentaireCommand = new RelayCommand(DeleteCommentaire);
    ...

    // Methods related to the RelayCommands
    private async void AddComment()
    {
        NavigationService.NavigateTo<EditCommentViewModel>(this, new object[] { _article, _titleStructure.Title }, true); 
    }

    private async void EditComment()
    {
        NavigationService.NavigateTo<EditCommentViewModel>(this, new object[] { _article, _titleStructure.Title, SelectedComment }, true);
    }

    private async void DeleteComment()
    {
        var test = SelectedComment;
    }

//RelaydCommands声明
...
公共RelayCommand AddCommentCommand{get；set；}
public RelayCommand EditCommentCommand{get；set；}
公共RelayCommand DeleteCommentCommand{get；set；}
...
//RelayCommand在构造函数中受影响
...
AddCommentaireCommand=新的RelayCommand（AddCommentaireCommand）；
EditCommentaireCommand=新的RelayCommand（EditCommentaireCommand）；
DeleteCommentaireCommand=新的RelayCommand（DeleteCommentaire）；
...
//与RelayCommands相关的方法
私有异步void AddComment（）
{
NavigationService.NavigateTo（这是一个新对象[]{u article，{u titleStructure.Title}，true）；
}
私有异步void EditComment（）
{
NavigationService.NavigateTo（这是一个新对象[]{u article，_titleStructure.Title，SelectedComment}，true）；
}
私有异步void DeleteComment（）
{
var测试=SelectedComment；
}

我没有遇到“AddComment”方法的任何问题，该方法是从AppBarButton调用的，但我从未输入方法“EditComment”和“deleteComent”，而我放置断点

我还试图用一个CallMethodAction替换MenuFlyoutItem的命令，但它没有改变任何东西：

    <!-- MenuFlyout - with CallMethodAction -->
    <FlyoutBase.AttachedFlyout>
        <MenuFlyout>
            <MenuFlyout.MenuFlyoutPresenterStyle>
                <Style TargetType="MenuFlyoutPresenter">
                    <Setter Property="Background" Value="{StaticResource ThemeBrush}"/>
                </Style>
            </MenuFlyout.MenuFlyoutPresenterStyle>
            <MenuFlyoutItem Text="Edit">
                <i:Interaction.Behaviors>
                    <core:EventTriggerBehavior EventName="Click">
                        <core:CallMethodAction MethodName="EditComment" />
                    </core:EventTriggerBehavior>
                </i:Interaction.Behaviors>
            </MenuFlyoutItem>
            <MenuFlyoutItem Text="Delete">
                <i:Interaction.Behaviors>
                    <core:EventTriggerBehavior EventName="Click">
                        <core:CallMethodAction MethodName="DeleteComment" />
                    </core:EventTriggerBehavior>
                </i:Interaction.Behaviors>
            </MenuFlyoutItem>
        </MenuFlyout>
    </FlyoutBase.AttachedFlyout>

---

=>有人能告诉我出了什么问题吗？

您正在listview中定义您的

弹出按钮

，因此datacontext被设置为

ViewModel上的
Comments
属性。
这意味着找不到您正在使用的两个命令

要解决此问题，您需要引用页面datacontext并使用它来定位命令

为您的
指定一个类似
x:name=“PageRoot”
的名称，并将命令的绑定更改为

{Binding ElementName=PageRoot，Path=DataContext.EditCommentCommand}
谢谢，它可以工作了，我现在可以输入deleteComent方法，但我不知道如何获取单击的注释以进行编辑或删除。。。