MVVM框架当中View层的引用添加之后,绑定数据无法显示

Question

请教一个问题,求帮助

<phone:PhoneApplicationPage xmlns:controls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls"  
    x:Class="PanoramaAndMVVM.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True"
 xmlns:my="crl-namespace:ViewModel" >
    <!--<phone:PhoneApplicationPage.Resources>
        <my:FruitViewModel x:Key="fruit"/>
    </phone:PhoneApplicationPage.Resources>-->
    <!--Panorama控件-->
....
    <controls:Panorama Title="my application"
                               Name="myPanorama">
        <controls:Panorama.Background>
            <ImageBrush ImageSource="Background.jpg"
                                Opacity=".5"/>
        </controls:Panorama.Background>

        <!--Panorama item-->
        <!--在Panorama控件中将上面定义好的FruitViewModel类资源赋值给DataContext属性，表示该控件内使用FruitViewModel类作为上下文数据-->
        <controls:PanoramaItem Header="水果" DataContext="FruitViewModel">
            <!--在listbox控件中绑定FruitViewModel类的AllFruit属性，AllFruit是ObservableCollection<Fruit>类型-->
            <ListBox Margin="0,0,1,0" ItemsSource="{Binding AllFruit}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <Image Height="80" Width="100" Source="{Binding Icon}" Margin="2,0,0,0"/>
                            <StackPanel Width="335">
                                <TextBlock Text="{Binding Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
                                <TextBlock Text="{Binding Description}" TextWrapping="Wrap" Margin="21,-6,8,20" Style="{StaticResource PhoneTextSubtleStyle}"/>
                            </StackPanel>
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </controls:PanoramaItem>