Является ли Prism AutoWireViewModel совместимым с MEF?

Question

Я пытаюсь совместить AutoWireViewModel с MefBootstrapper для перехода между представлениями в различных модулях. Однако я получаю исключение:

Установить свойство 'Prism.Mvvm.ViewModelLocator.AutoWireViewModel' бросил исключение

Точки исключения для этой строки кода: xmlns:prism="http://www.codeplex.com/prism"

XAML:

<UserControl x:Class="Login.Views.LoginForm" 
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
      xmlns:prism="http://www.codeplex.com/prism" 
      prism:ViewModelLocator.AutoWireViewModel="True" Width="350"> 

    <Grid x:Name="LayoutRoot"> 
     <Grid.Background> 
      <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> 
       <GradientStop Color="#FF7B97D4" /> 
       <GradientStop Color="#FF244C8D" Offset="1" /> 
      </LinearGradientBrush> 
     </Grid.Background> 
     <Grid.ColumnDefinitions> 
      <ColumnDefinition Width="100" /> 
      <ColumnDefinition Width="*" /> 
     </Grid.ColumnDefinitions> 
     <Grid.RowDefinitions> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition Height="*" /> 

     </Grid.RowDefinitions> 

     <TextBlock Grid.Row="0" Text="Login" TextWrapping="Wrap" Grid.RowSpan="1" Grid.ColumnSpan="2" FontSize="18" Foreground="#FF2F3806" Margin="8,8,8,8" /> 

     <Label Grid.Row="1" Margin="10,10,10,10">username:</Label> 
     <TextBox x:Name="txtUsername" Text="{Binding UserName}" Grid.Row="1" Grid.Column="1" Margin="10,10,10,10" VerticalContentAlignment="Center"></TextBox> 
     <Label Grid.Row="2" Margin="10">password:</Label> 
     <PasswordBox x:Name="txtPassword" Grid.Row="2" Grid.Column="1" Margin="10,10,10,10" VerticalContentAlignment="Center" /> 
     <Button x:Name="btnLogin" Grid.Row="3" Grid.RowSpan="1" Grid.ColumnSpan="2" Margin="10,10,10,10" Content="Log In" FontWeight="Bold" /> 
     <TextBlock x:Name="txtMsg" Grid.Row="4" Grid.RowSpan="1" Grid.ColumnSpan="2" Margin="10,10,10,10" /> 

    </Grid> 

</UserControl> 

Вид:

using System.ComponentModel.Composition; 
using System.Windows.Controls; 

namespace Login.Views 
{ 
    [Export("LoginForm")] 
    public partial class LoginForm : UserControl 
    { 

     public LoginForm() 
     { 
      InitializeComponent(); 
     } 
    } 
} 

ViewModel:

using Prism.Mvvm; 

namespace Login.ViewModels 
{ 
    public class LoginFormViewModel : BindableBase 
    { 

     private string _username = "unamegoeshere"; 
     public string UserName 
     { 
      get { return _username; } 
      set { SetProperty(ref _username, value); } 
     } 
    } 
} 

Shell:

[Export] 
public partial class Shell : Window, IPartImportsSatisfiedNotification 
{ 
    private const string InitialModuleName = "LoginModule"; 
    private static Uri InitialViewUri = new Uri("/LoginForm", UriKind.Relative); 
    public Shell() 
    { 
     InitializeComponent(); 
    } 

[Import(AllowRecomposition = false)] 
public IModuleManager ModuleManager; 

[Import(AllowRecomposition = false)] 
public IRegionManager RegionManager; 

public void OnImportsSatisfied() 
{ 
    this.ModuleManager.LoadModuleCompleted += 
     (s, e) => 
     { 
      if (e.ModuleInfo.ModuleName == InitialModuleName) 
      { 
       this.RegionManager.RequestNavigate(
        RegionNames.MainContentRegion, 
        InitialViewUri); 
      } 
     }; 
} 

Answer 1

LoginFormViewModel необходим атрибут экспорта.

[Export] 
public class LoginFormViewModel ... 

И добавьте также пространство имен System.ComponentModel.Compositon.