public interface ISay 
 { 
   void SaySth(); 
 } 

namespace Assembly1 
{ 
  public class OneSay : ISay 
  { 
    public void SaySth() 
    { 
      Console.WriteLine("我来自程序集1"); 
    } 
  } 
} 

class Program 
  { 
    static void Main(string[] args) 
    { 
      foreach (var say in GetSpeakers()) 
      { 
        say.SaySth(); 
      } 
    } 
    static List<ISay> GetSpeakers() 
    { 
      List<ISay> result = new List<ISay>(); 
      //获取项目根目录下的Plugins文件夹 
      string dir = Directory.GetCurrentDirectory(); 
      //遍历目标文件夹中包含dll后缀的文件 
      foreach (var file in Directory.GetFiles(dir + @"\", "*.dll")) 
      { 
        //加载程序集 
        var asm = Assembly.LoadFrom(file); 
        //遍历程序集中的类型 
        foreach (var type in asm.GetTypes()) 
        { 
          //如果是ISay接口 
          if (type.GetInterfaces().Contains(typeof (ISay))) 
          { 
            //创建接口类型实例 
            var isay = Activator.CreateInstance(type) as ISay; 
            if (isay != null) 
            { 
              result.Add(isay); 
            } 
          } 
        } 
      } 
      return result; 
    }

namespace Assembly2 
{ 
  public class TwoSay : ISay 
  { 
    public void SaySth() 
    { 
      Console.WriteLine("我来自程序集2"); 
    } 
  } 
}