MEF 基础简介 三

 mef导出类的方法和属性

首先来说导出属性，因为这个比较简单，和导出类差不多，先来看看代码，主要看我加注释的地方，musicbook.cs中的代码如下：

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.componentmodel.composition;

namespace mefdemo
{
   [export("musicbook")]
   public class musicbook : ibookservice
   {
      //导出私有属性
      [export(typeof(string))]
      private string _privatebookname = "private music bookname";

      //导出公有属性
      [export(typeof(string))]
      public string _publicbookname = "public music bookname";


      public string bookname { get; set; }

   }

   [export("mathbook", typeof(ibookservice))]
   public class mathbook : ibookservice
   {
      public string bookname { get; set; }

      public string getbookname()
      {
         return "mathbook";
      }
   }

   [export("historybook", typeof(ibookservice))]
   public class historybook : ibookservice
   {
      public string bookname { get; set; }

      public string getbookname()
      {
         return "historybook";
      }
   }

}

program.cs中的代码如下：

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.reflection;
using system.componentmodel.composition;
using system.componentmodel.composition.hosting;

namespace mefdemo
{
   class program
   {
      [importmany("mathbook")]
      public ienumerable<object> services { get; set; }

      //导入属性，这里不区分public还是private
      [importmany]
      public list<string> inputstring { get; set; }

      static void main(string[] args)
      {
         program pro = new program();
         pro.compose();
         if (pro.services != null)
         {
            foreach (var s in pro.services)
            {
               var ss = (ibookservice)s;
               console.writeline(ss.getbookname());
            }
         }
         foreach (var str in pro.inputstring)
         {
            console.writeline(str);
         }

         console.read();
      }
      
      private void compose()
      {
         var catalog = new assemblycatalog(assembly.getexecutingassembly());
         compositioncontainer container = new compositioncontainer(catalog);
         container.composeparts(this);
      }
   }
}

下面还用foreach遍历输出属性的值，运行即可查看到结果。最后我会附上源码供大家下载，这里就不再截图了。

下面说导出方法吧，同理无论是公有方法还是私有方法都是可以导出的，musicbook代码如下：

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.componentmodel.composition;

namespace mefdemo
{
   [export("musicbook")]
   public class musicbook : ibookservice
   {
      //导出私有属性
      [export(typeof(string))]
      private string _privatebookname = "private music bookname";

      //导出公有属性
      [export(typeof(string))]
      public string _publicbookname = "public music bookname";


      public string bookname { get; set; }

      //导出公有方法
      [export(typeof(func<string>))]
      public string getbookname()
      {
         return "musicbook";
      }

      //导出私有方法
      [export(typeof(func<int, string>))]
      private string getbookprice(int price)
      {
         return "$" + price;
      }
   }

   [export("mathbook", typeof(ibookservice))]
   public class mathbook : ibookservice
   {
      public string bookname { get; set; }

      public string getbookname()
      {
         return "mathbook";
      }
   }

   [export("historybook", typeof(ibookservice))]
   public class historybook : ibookservice
   {
      public string bookname { get; set; }

      public string getbookname()
      {
         return "historybook";
      }
   }

}

program中的代码如下：

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.reflection;
using system.componentmodel.composition;
using system.componentmodel.composition.hosting;

namespace mefdemo
{
   class program
   {
      [importmany("mathbook")]
      public ienumerable<object> services { get; set; }

      //导入属性，这里不区分public还是private
      [importmany]
      public list<string> inputstring { get; set; }

      //导入无参数方法
      [import]
      public func<string> methodwithoutpara { get; set; }

      //导入有参数方法
      [import]
      public func<int,string> methodwithpara { get; set; }

      static void main(string[] args)
      {
         program pro = new program();
         pro.compose();
         if (pro.services != null)
         {
            foreach (var s in pro.services)
            {
               var ss = (ibookservice)s;
               console.writeline(ss.getbookname());
            }
         }
         foreach (var str in pro.inputstring)
         {
            console.writeline(str);
         }

         //调用无参数方法
         if (pro.methodwithoutpara != null)
         {
            console.writeline(pro.methodwithoutpara());
         }
         //调用有参数方法
         if (pro.methodwithpara != null)
         {
            console.writeline(pro.methodwithpara(3000));
         }

         console.read();
      }
      
      private void compose()
      {
         var catalog = new assemblycatalog(assembly.getexecutingassembly());
         compositioncontainer container = new compositioncontainer(catalog);
         container.composeparts(this);
      }
   }
}

导入导出方法用到了func<t>委托，当然没有返回值的话可以用action<t>委托，关于委托这里就不多说了，大家可以自行百度。