Question

我正在为学校制作带MVVM Light的Windows 8.1应用程序。我面临的问题是使用Command属性。我希望将单击的Movie对象发送到不同的页面并显示有关它的更多信息。但是绑定失败：绑定不在我的DataContext中搜索，而是在我的Movie模型中搜索命令。：（

错误讯息：

错误：BindingExpression路径错误：＆＃39; ShowInfoMovieCommand＆＃39;找不到＆＃39; Howest.NMCT.RottenTomatoes.Models.Movie，Howest.NMCT.RottenTomatoes.Models，Version = 1.0.0.0，Culture = neutral，PublicKeyToken = null＆＃39;。 BindingExpression：Path =＆＃39; ShowInfoMovieCommand＆＃39; DataItem =＆＃39; Howest.NMCT.RottenTomatoes.Models.Movie，Howest.NMCT.RottenTomatoes.Models，Version = 1.0.0.0，Culture = neutral，PublicKeyToken = null＆＃39 ;;目标元素是＆＃39; Microsoft.Xaml.Interactions.Core.InvokeCommandAction＆＃39; （名称=＆＃39;空＆＃39）;目标财产是＆＃39; Command＆＃39; （键入＆＃39; ICommand＆＃39;）

我视图中的我的XAML代码（数据上下文设置在页面顶部）

DataContext="{Binding GroupedItemsPageViewModel, Source={StaticResource Locator}}"

用于显示电影的ItemTemplate

<DataTemplate x:Key="RottenTomatoesMovieItemTemplate">
    <Grid HorizontalAlignment="Left" Width="250" Height="230">
        <Interactivity:Interaction.Behaviors>
            <Core:EventTriggerBehavior EventName="Tapped">
                <Core:InvokeCommandAction **Command="{Binding ShowInfoMovieCommand}" CommandParameter="{Binding id}"/>**
            </Core:EventTriggerBehavior>
        </Interactivity:Interaction.Behaviors>
        <Border>
            <Image Source="{Binding posters.original}" Stretch="UniformToFill"/>
        </Border>
        <Grid VerticalAlignment="Bottom" Background="#B2CF4400" Height="50">
            <Grid.RowDefinitions>
                <RowDefinition Height="18*"/>
                <RowDefinition Height="21*"/>
                <RowDefinition Height="11*"/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="24*"/>
                <ColumnDefinition Width="101*"/>
            </Grid.ColumnDefinitions>
            <TextBlock x:Name="TitleTextblock" Text="{Binding title}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}"  Margin="15,0,0,0" Grid.ColumnSpan="2"/>
            <Image Source="{Binding ratings.critics_rating, Converter={StaticResource RatingToPhotoConverter}}" Width="15" HorizontalAlignment="Left" Margin="15,0,0,0" Grid.Row="1"/>
            <TextBlock Text="{Binding ratings, Converter={StaticResource RatingToPercentFormat}}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Grid.Column="1" Grid.Row="1" />
        </Grid>
    </Grid>
</DataTemplate>

我的页面ViewModel（GroupedItemsPageViewModel）

private void ShowInfoMovie(object clickedMovie)
{
    Debug.WriteLine(clickedMovie);
}

private RelayCommand<object> _showInfoMovieCommand;
public RelayCommand<object> ShowInfoMovieCommand
{
    get
    {
        if (_showInfoMovieCommand == null)
        {
            _showInfoMovieCommand = new RelayCommand<object>(
                param => this.ShowInfoMovie(param)
                );
        }
        return _showInfoMovieCommand;
    }
}

Answer 1

没关系自己找到它。在我的datatemplate中，我的命令绑定应该是：

<Interactivity:Interaction.Behaviors>
    <Core:EventTriggerBehavior EventName="Tapped">
        <Core:InvokeCommandAction Command="{Binding DataContext.ShowInfoMovieCommand, ElementName=pageRoot}" CommandParameter="{Binding}"/>
    </Core:EventTriggerBehavior>
</Interactivity:Interaction.Behaviors>

在我的ViewModel中，最好抓住我自己的模型（电影）

private void SetSelectedMovieDestinationView(Movie clickedMovie)
{
//Do Stuff
}

命令未找到

1 个答案: