Model-View-ViewModel(MVVM) with MEF

今天看David Wynne 写的一篇如果在MVVM中使用MEF进行扩展的文章,总的来说例子写的很好,可是有一个很命的地方,View是硬编码(hardcoded)到Main window中的,我就借花献佛,把它的例子稍稍改一下,以使它真正的好扩展。

 

基本上改动不大,直接贴代码吧

App.cs 

public partial class App : Application
{
private static CompositionContainer _container;

internal static CompositionContainer Container
{
get
{
return _container;
}
}

[Import(
"MainWindow")]
public new Window MainWindow
{
get { return base.MainWindow; }
set { base.MainWindow = value; }
}

protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
var catalog
= new AggregateCatalog();
catalog.Catalogs.Add(
new AssemblyCatalog(Assembly.GetExecutingAssembly()));
//catalog.Catalogs.Add(new DirectoryCatalog("Extensions"));
_container = new CompositionContainer(catalog);

var batch
= new CompositionBatch();
batch.AddPart(
this);

try
{
_container.Compose(batch);
MainWindow.Show();
}
catch
{
Shutdown();
}

}
}

 

下面是对应的MainWindow.Xaml

 

<Window x:Class="WpfApplication1.MainWindow"
xmlns
="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x
="http://schemas.microsoft.com/winfx/2006/xaml"
Loaded
="Window_Loaded"
Title
="MainWindow">
<StackPanel x:Name="WidgetsPanel"></StackPanel>
</Window>

MainWindow.xaml.cs

 

代码
[Export("MainWindow", typeof(Window))]
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}

[ImportMany(
"wpf1app", typeof(UIElement))]
public Lazy<UIElement>[] Widgets { get; set; }

private void Window_Loaded(object sender, RoutedEventArgs e)
{
foreach (var widget in Widgets)
{
this.WidgetsPanel.Children.Add(widget.Value);
}
}
}

 

Widget1.Xaml

 

<UserControl x:Class="WpfApplication1.Component1"
xmlns
="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x
="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc
="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d
="http://schemas.microsoft.com/expression/blend/2008"
Loaded
="UserControl_Loaded"
>
<Grid>
<Button Content="{Binding Path=Content}" Background="{Binding Path=BackgroudColor}" />
</Grid>
</UserControl>

Widget1.xaml.cs

 

 

 

 

代码
[Export("wpf1app", typeof(UIElement))]
public partial class Component1 : UserControl
{
public Component1()
{
InitializeComponent();
}

[Import(
typeof(Widget1ModelView))]
public Widget1ModelView ViewModel
{
get;
private set;
}

private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
this.DataContext = ViewModel;
}
}

 

 

 

Widget1ModelView

 

代码
[Export(typeof(Widget1ModelView))]
public class Widget1ModelView
{
public string Content
{
get
{
return "Click Me";
}
}

public string BackgroudColor
{
get
{
return "Red";
}
}
}

 

posted @ 2010-01-22 16:46 芭蕉 阅读(...) 评论(...) 编辑 收藏