C# MEF导入没有任何内容

我想使用mef添加插件。在插件中，主程序是否添加了从其他插件导入的内容，如ioc

现在我可以成功地得到这个插件，但在插件中无法得到导入的一个

下面是我的代码。登录插件。服务为空

接口项目

public class Plugin1Service : IService
{
    [Import(typeof(Ilog))]
    public Ilog Log { get; private set; }//todo:Log is null

    public void DoSomeThing()
    {
        Log.Log("test from Plugin1");
    }
}

[Export(typeof(IPlugin))]
public class Plugin1Info : IPlugin
{
    public string PluginName => "Plugin1";

    public IService Service =>new Plugin1Service();
}

[Export(typeof(Ilog))]
public class Console1 : Ilog
{
    public void Log(string log)
    {
        Console.WriteLine(log);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var catalogs = new DirectoryCatalog(Directory.GetCurrentDirectory());
        var container = new CompositionContainer(catalogs);

        var plugin = container.GetExportedValue<IPlugin>();
        Console.WriteLine($"{plugin.PluginName}");
        plugin.Service.DoSomeThing();

        Console.ReadKey(true);
    }
}

Ilog.cs

IServece.cs

IPlugin.cs

Plugin1项目

public class Plugin1Service : IService
{
    [Import(typeof(Ilog))]
    public Ilog Log { get; private set; }//todo:Log is null

    public void DoSomeThing()
    {
        Log.Log("test from Plugin1");
    }
}

[Export(typeof(IPlugin))]
public class Plugin1Info : IPlugin
{
    public string PluginName => "Plugin1";

    public IService Service =>new Plugin1Service();
}

[Export(typeof(Ilog))]
public class Console1 : Ilog
{
    public void Log(string log)
    {
        Console.WriteLine(log);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var catalogs = new DirectoryCatalog(Directory.GetCurrentDirectory());
        var container = new CompositionContainer(catalogs);

        var plugin = container.GetExportedValue<IPlugin>();
        Console.WriteLine($"{plugin.PluginName}");
        plugin.Service.DoSomeThing();

        Console.ReadKey(true);
    }
}

ConsoleLog项目

public class Plugin1Service : IService
{
    [Import(typeof(Ilog))]
    public Ilog Log { get; private set; }//todo:Log is null

    public void DoSomeThing()
    {
        Log.Log("test from Plugin1");
    }
}

[Export(typeof(IPlugin))]
public class Plugin1Info : IPlugin
{
    public string PluginName => "Plugin1";

    public IService Service =>new Plugin1Service();
}

[Export(typeof(Ilog))]
public class Console1 : Ilog
{
    public void Log(string log)
    {
        Console.WriteLine(log);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var catalogs = new DirectoryCatalog(Directory.GetCurrentDirectory());
        var container = new CompositionContainer(catalogs);

        var plugin = container.GetExportedValue<IPlugin>();
        Console.WriteLine($"{plugin.PluginName}");
        plugin.Service.DoSomeThing();

        Console.ReadKey(true);
    }
}

主要项目

public class Plugin1Service : IService
{
    [Import(typeof(Ilog))]
    public Ilog Log { get; private set; }//todo:Log is null

    public void DoSomeThing()
    {
        Log.Log("test from Plugin1");
    }
}

[Export(typeof(IPlugin))]
public class Plugin1Info : IPlugin
{
    public string PluginName => "Plugin1";

    public IService Service =>new Plugin1Service();
}

[Export(typeof(Ilog))]
public class Console1 : Ilog
{
    public void Log(string log)
    {
        Console.WriteLine(log);
    }
}

class Program
{
    static void Main(string[] args)
    {
        var catalogs = new DirectoryCatalog(Directory.GetCurrentDirectory());
        var container = new CompositionContainer(catalogs);

        var plugin = container.GetExportedValue<IPlugin>();
        Console.WriteLine($"{plugin.PluginName}");
        plugin.Service.DoSomeThing();

        Console.ReadKey(true);
    }
}

类程序
{
静态void Main（字符串[]参数）
{
var catalogs=newdirectorycatalog（Directory.GetCurrentDirectory（））；
var容器=新的合成容器（目录）；
var plugin=container.GetExportedValue（）；
Console.WriteLine（$“{plugin.PluginName}”）；
plugin.Service.DoSomeThing（）；
Console.ReadKey（true）；
}
}

---

运行该程序时，登录plugin.Service为null（可以查看“todo:”）。如何获取日志项？

您创建了自己的服务实例，因此MEF不提供

ILog

实例

当您让MEF创建您的服务时，它将在Log属性上拾取。因此：

    [Export(typeof(IService))] // Add this export
    public class Plugin1Service : IService
    {
        [Import(typeof(Ilog))]
        public Ilog Log { get; private set; }//todo:Log is null

        public void DoSomeThing()
        {
            Log.Log("test from Plugin1");
        }
    }

    [Export(typeof(IPlugin))]
    public class Plugin1Info : IPlugin
    {
        public string PluginName => "Plugin1";

        [Import] // Import the service
        public IService Service { get; set; }
    }

---

如果您必须自己创建服务，您可以要求MEF通过调用

CompositionContainer

Tanks to@Pidon上的

SatisfyImportsOnce

来填写所有导入，我得到了