如何在.Net 4.0中使用DLR與MEF？

Question

MEF團隊承諾MEF將支持.Net 4.0中的DLR插件。它是否已經發生，我可以[導入]一些IronPython對象？

如果是的話，任何指向該主題的鏈接都會有所幫助。

Answer 1

默認編程模型不支持DLR，但可以編寫其他編程模型來支持它，並且可以與默認編程模型一起使用。

• Blog post on the MEF Primitives（它們用於創建編程模型）。
• Blog post with some ideas on how a Ruby programming model could work
• How to write a custom command for Intellipad（Intellipad使用MEF和Python編程模型）

Answer 2

我知道這是舊的，但你可以看看http://github.com/JogoShugh/IronPythonMef或查找NuGet包。

我從Bruno Lopes的一個名爲ILoveLucene的項目中抽出了一些代碼，並將它變成了這個獨立的repo和package。它剛剛開始，但包含一些示例和單元測試。

下面是一個例子：

using System; 
using System.Collections.Generic; 
using System.ComponentModel.Composition; 
using System.ComponentModel.Composition.Hosting; 
using System.ComponentModel.Composition.Primitives; 
using System.Reflection; 
using IronPython.Hosting; 
using IronPythonMef; 

public interface IMessenger 
{ 
    string GetMessage(); 
} 

public interface IConfig 
{ 
    string Intro { get; } 
} 

/// <summary> 
/// Gets exported from IronPython into the CLR Demo instance. 
/// </summary> 
public static class PythonScript 
{ 
    public static readonly string Code = 
@" 
@export(IMessenger) 
class PythonMessenger(IMessenger): 
    def GetMessage(self): 
     return self.config.Intro + ' from IronPython' 

    @import_one(IConfig) 
    def import_config(self, config): 
     self.config = config 
"; 
} 

/// <summary> 
/// Also gets exported into the Demo instance. 
/// </summary> 
[Export(typeof(IMessenger))] 
public class ClrMessenger : IMessenger 
{ 
    [Import(typeof(IConfig))] 
    public IConfig Config { get; set; } 

    public string GetMessage() 
    { 
     return Config.Intro + " from C#!"; 
    } 
} 

/// <summary> 
/// This will get imported into both the IronPython class and ClrMessenger. 
/// </summary> 
[Export(typeof(IConfig))] 
public class Config : IConfig 
{ 
    public string Intro 
    { 
     get { return "Hello"; } 
    } 
} 

public class Demo 
{ 
    [ImportMany(typeof(IMessenger))] 
    public IEnumerable<IMessenger> Messengers { get; set; } 

    public Demo() 
    { 
     // Create IronPython 
     var engine = Python.CreateEngine(); 
     var script = engine.CreateScriptSourceFromString(PythonScript.Code); 

     // Configure the engine with types 
     var typesYouWantPythonToHaveAccessTo = new[] { typeof(IMessenger), typeof(IConfig) }; 
     var typeExtractor = new ExtractTypesFromScript(engine); 
     var exports = typeExtractor.GetPartsFromScript(script, 
      typesYouWantPythonToHaveAccessTo); 

     // Compose with MEF 
     var catalog = new AssemblyCatalog(Assembly.GetExecutingAssembly()); 
     var container = new CompositionContainer(catalog); 
     var batch = new CompositionBatch(exports, new ComposablePart[] { }); 
     container.Compose(batch); 
     container.SatisfyImportsOnce(this); 
    } 

    public static void Main(string[] args) 
    { 
     var demo = new Demo(); 

     foreach (var messenger in demo.Messengers) 
     { 
      Console.WriteLine(messenger.GetMessage()); 
     } 

     Console.Read(); 
    } 
} 

的輸出是簡單的：

Hello from IronPython! 
Hello from C#!