Question

我在ViewModel上有一个命令，我用它来导航到详细信息页面

public class InstalledMetersListViewModel : MvxViewModel
    , IMvxServiceConsumer<IInstallMeterRepository>
{
    public List<InstalledMeterListItemViewModel> List { get; set; } 

    public InstalledMetersListViewModel()
    {
        List = new List<InstalledMeterListItemViewModel>();
        foreach (var meter in this.GetService<IInstallMeterRepository>().GetInstalledMeters())
        {
            List.Add(new InstalledMeterListItemViewModel { Serial = meter.Serial, Description = meter.Description });
        }
    }

    public IMvxCommand ShowDetailsCommand
    {
        get
        {
            return new MvxRelayCommand<InstalledMeterListItemViewModel>(type => RequestNavigate<InstalledMeterListItemViewModel>(new {serial = type.Serial.ToString()}));
        }
    }
}

使用此视图

<ListBox ItemsSource="{Binding List}" x:Name="TheListBox">
    <ListBox.ItemContainerStyle>
        <Style TargetType="ListBoxItem">
            <Setter Property="HorizontalContentAlignment" Value="Stretch"></Setter>
        </Style>
    </ListBox.ItemContainerStyle>
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Border BorderThickness="5,5,5,5" BorderBrush="White">
                <Grid Width="auto" HorizontalAlignment="Stretch" >
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="1*"/>
                        <ColumnDefinition Width="Auto"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition />
                        <RowDefinition />
                    </Grid.RowDefinitions>

                    <TextBlock Text="S/N"/>
                    <TextBlock Text=" : " Grid.Column="1"/>
                    <TextBlock Text="{Binding Serial}" Grid.Column="2"/>

                    <TextBlock Text="Description" Grid.Row="1"/>
                    <TextBlock Text=" : " Grid.Column="1" Grid.Row="1"/>
                    <TextBlock Text="{Binding Description}" Grid.Column="2" Grid.Row="1"/>

                    <Button Content="Details" Grid.Column="3" Grid.RowSpan="2" Command="{Binding Path=DataContext.ShowDetailsCommand, ElementName=TheListBox}" CommandParameter="{Binding}"/>
                </Grid>
            </Border>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

我导航到的ViewModel是

public class InstalledMeterListItemViewModel : MvxViewModel,
    IMvxServiceConsumer<IInstallMeterRepository>
{

    public InstalledMeterListItemViewModel(string serial)
    {
        IInstalledMeter meter = this.GetService<IInstallMeterRepository>().GetMeter(Convert.ToDouble(serial));
        Description = meter.Description;
        Serial = meter.Serial;
    }

    public InstalledMeterListItemViewModel()
    {

    }

访问对象时出现问题 - 很可能是因为匿名对象被生成为内部 - 请参阅Anonymous types and Get accessors on WP7.1?

但是我不使用任何内部类，所以我不知道如何解决这个问题

Answer 1

这一行：

return new MvxRelayCommand<InstalledMeterListItemViewModel>(
         vm => RequestNavigate<InstalledMeterListItemViewModel>(
              new {serial = type.Serial.ToString()}));

创建匿名类的实例

该匿名类是由编译器生成的（使用像Reflector这样的工具来查看它）

编译器将其生成为internal

即。编译器创建一个类似

的类

 internal class Anonymous_Mangled_Name_1223345tHER
 {
     public string serial { get; set; }
 }

然后将代码重写为：

return new MvxRelayCommand<InstalledMeterListItemViewModel>(
         vm => RequestNavigate<InstalledMeterListItemViewModel>(
              new Anonymous_Mangled_Name_1223345tHER
              {
                  serial = type.Serial.ToString()
              }));

为了反映和使用这个类，Cirrious.MvvmCross中的代码需要访问它...

这就是您需要InternalsVisibleTo - http://msdn.microsoft.com/en-us/library/system.runtime.compilerservices.internalsvisibletoattribute.aspx

的原因

有关要添加的行的示例，请参阅Conference-AssemblyInfo.cs的最后一行。

[assembly: InternalsVisibleTo("Cirrious.MvvmCross")]

注意：对于旧的“主”分支，这是：

[assembly: InternalsVisibleTo("Cirrious.MvvmCross.WindowsPhone")] 
// should really also add Cirrious.MvvmCross.Touch - but mono runtime doesn't care 
// should really also add Cirrious.MvvmCross.Droid - but mono runtime doesn't care

在WP7.1上使用MvvmCross在VM上向VM发送参数时出现异常

1 个答案: