public class MefBootstrapper : Bootstrapper<IShell>{private CompositionContainer container;protected override void Configure(){/*CompositionContainer 对象在应用程序中有两种的主要用途。首先，它跟踪哪些部分可用于组合、它们的依赖项，并且充当任何指定组合的上下文。其次，它提供了应用程序可以启动组合的方法、获取组合部件的实例，或填充可组合部件的依存关系。部件可直接用于容器，或通过 Catalog 属性来用于容器。在此 ComposablePartCatalog 中可发现的所有部件都可以供容器来满足导入，还包括直接添加的任何部件。*/ container = new CompositionContainer(new AggregateCatalog(AssemblySource.Instance.Select(x => new AssemblyCatalog(x))));var batch = new CompositionBatch();var dockScreenManager = new DockScreenManager();batch.AddExportedValue<IWindowManager>(new WindowManager());//將指定的导出加入至 CompositionBatch 物件batch.AddExportedValue<IDockScreenManager>(dockScreenManager);batch.AddExportedValue<IEventAggregator>(new EventAggregator());batch.AddExportedValue(container);container.Compose(batch);//在容器上执行组合，包括指定的 CompositionBatch 中的更改}protected override object GetInstance(Type serviceType, string key){var contract = string.IsNullOrEmpty(key) ? AttributedModelServices.GetContractName(serviceType) : key;//获取指定类型的规范协定名称var exports = container.GetExportedValues<object>(contract);//返回具有从指定的类型参数派生的协定名称的已导出对象。如果不是正好有一个匹配的已导出对象，则将引发异常。if (exports.Any())return exports.First();throw new Exception(string.Format("Could not locate any instances of contract {0}.", contract));}protected override IEnumerable<object> GetAllInstances(Type serviceType){return container.GetExportedValues<object>(AttributedModelServices.GetContractName(serviceType));}protected override void BuildUp(object instance){container.SatisfyImportsOnce(instance);//满足指定的 ComposablePart 对象的导入，而无需注册该对象以进行重新组合。}}

<Application x:Class="DemoApplication.App"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:local="clr-namespace:DemoApplication"><Application.Resources><ResourceDictionary><ResourceDictionary.MergedDictionaries><ResourceDictionary><local:MefBootstrapper x:Key="bootstrapper" /></ResourceDictionary></ResourceDictionary.MergedDictionaries></ResourceDictionary></Application.Resources>
</Application>

  public interface IShell{}

<MetrolControls:MetroWindow x:Class="DemoApplication.ShellView"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:MetrolControls="clr-namespace:MahApps.Metro.Controls;assembly=MahApps.Metro"Title="ShellView" Height="500" Width="800"><Window.Resources><ResourceDictionary><ResourceDictionary.MergedDictionaries><ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Colours.xaml"/><ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml"/><ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml"/></ResourceDictionary.MergedDictionaries></ResourceDictionary></Window.Resources><Grid><ContentControl  x:Name="DockContent" Margin="0,2,0,0" Grid.Row="0"/></Grid>
</MetrolControls:MetroWindow>

 [Export(typeof(IShell))]class ShellViewModel:IShell{[Import]public IScreen DockContent { get; set; }}

<UserControl x:Class="DemoApplication.Views.DockView"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" mc:Ignorable="d" xmlns:avalonDock="http://avalondock.codeplex.com"d:DesignHeight="300" d:DesignWidth="800"><UserControl.Resources><avalonDock:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter"/></UserControl.Resources><Grid><Grid x:Name="layoutRoot"><avalonDock:DockingManager  Grid.Row="1" x:Name="dockManager"  AllowMixedOrientation="True"  ><avalonDock:DockingManager.Theme><avalonDock:MetroTheme/></avalonDock:DockingManager.Theme><avalonDock:DockingManager.LayoutItemTemplate><DataTemplate><ContentControl IsTabStop="False" /></DataTemplate></avalonDock:DockingManager.LayoutItemTemplate><avalonDock:LayoutRoot><avalonDock:LayoutPanel  Orientation="Horizontal"  ><avalonDock:LayoutAnchorablePaneGroup DockWidth="200"    Orientation="Vertical"  ><avalonDock:LayoutAnchorablePane  ><avalonDock:LayoutAnchorable Title="left" ></avalonDock:LayoutAnchorable></avalonDock:LayoutAnchorablePane></avalonDock:LayoutAnchorablePaneGroup><avalonDock:LayoutPanel  Orientation="Vertical"  ><avalonDock:LayoutDocumentPaneGroup Orientation="Horizontal"><avalonDock:LayoutDocumentPane   ><avalonDock:LayoutDocument Title="main"></avalonDock:LayoutDocument></avalonDock:LayoutDocumentPane></avalonDock:LayoutDocumentPaneGroup><avalonDock:LayoutAnchorablePaneGroup DockHeight="100"   Orientation="Horizontal"  ><avalonDock:LayoutAnchorablePane  ><avalonDock:LayoutAnchorable Title="bottom" ></avalonDock:LayoutAnchorable></avalonDock:LayoutAnchorablePane></avalonDock:LayoutAnchorablePaneGroup></avalonDock:LayoutPanel><avalonDock:LayoutAnchorablePaneGroup DockWidth="200"    Orientation="Horizontal"  ><avalonDock:LayoutAnchorablePane ><avalonDock:LayoutAnchorable Title="Right" ></avalonDock:LayoutAnchorable></avalonDock:LayoutAnchorablePane></avalonDock:LayoutAnchorablePaneGroup></avalonDock:LayoutPanel></avalonDock:LayoutRoot></avalonDock:DockingManager></Grid></Grid>
</UserControl>

    [Export(typeof(IScreen))]public class DockViewModel : Screen{}