Windows Phone 7上的绑定不起作用

Question

我在WP 7上有一个奇怪的绑定问题。代码在WP8上可以正常工作，但是没有问题，但是在WP7上运行相同（以下）代码时，绑定不起作用，TextBlock.Text为“”。 这是代码（绑定是在第二个TextBlock的Text属性上设置的）：

    <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,35">
        <ListBox x:Name="MainListBox" Margin="0,0,-12,0" SelectionChanged="MainListBox_SelectionChanged">

            <StackPanel x:Name="MeasurementUnitPropertyPanel" toolkit:TiltEffect.IsTiltEnabled="True" Margin="12,0,0,0" Orientation="Horizontal" MinHeight="100">
                <TextBlock x:Name="MeasurementUnitPropertyLabel" Width="235" Margin="0,30,0,0" HorizontalAlignment="Left" Text="{Binding Path=AppResources.MeasurementUnitPropertyLabel, Source={StaticResource LocalizedStrings}}" Style="{StaticResource PhoneTextLargeStyle}" FontSize="28">
                    <TextBlock.Foreground>
                        <SolidColorBrush Color="Black"/>
                    </TextBlock.Foreground>
                </TextBlock>
                <TextBlock x:Name="MeasurementUnitPropertyValue" Width="185" Margin="0,30,0,0" TextAlignment="Right" Text="{Binding MeasurementUnit}" Style="{StaticResource PhoneTextLargeStyle}" FontSize="28">
                    <TextBlock.Foreground>
                        <SolidColorBrush Color="{StaticResource DarkGrayThemeColor}"/>
                    </TextBlock.Foreground>
                </TextBlock>
            </StackPanel>

...

然后我在OnNavigatedTo方法中设置DataContext（或在构造函数中，问题是相同的）...

// When page is navigated to set data context to selected item in list
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        viewModel = new ClimateSettingsViewModel();
        DataContext = viewModel;
        //MeasurementUnitPropertyValue.DataContext = viewModel.MeasurementUnit; //This does not work too...

        //Other stuff...
    }

（一部分）ClimateSettingsViewModel类：

class ClimateSettingsViewModel : INotifyPropertyChanged
{
    /// <summary>
    /// Sample ViewModel property; this property is used in the view to display its value using a Binding.
    /// </summary>
    /// <returns></returns>
    public String MeasurementUnit
    {
        get
        {
            return ClimateSettings.MeasurementUnitValues[App.UserData.SelectedConfiguration.ClimateSettings.MeasurementUnit];
        }
        /*
        set
        {
            if (value != ClimateSettings.MeasurementUnitValues[App.UserData.SelectedConfiguration.ClimateSettings.MeasurementUnit])
            {
                App.UserData.SelectedConfiguration.ClimateSettings.MeasurementUnit = value;
                NotifyPropertyChanged("MeasurementUnit");
            }
        }*/
    }


    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(String propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (null != handler)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

应用平台是WP OS 7.1。 提前致谢！

Answer 1

经过进一步调查后，Windows Phone 7和Windows Phone 8实施了不同的反射。

在Windows Phone 7上，如果您尝试访问私有或内部功能，则将获得MethodAccessException但在Windows Phone 8上它将正常工作。

调试时只需打开所有异常，此错误就会跳起。