c#: abstract class using interfaces
public abstract class MyClass : IDisposable, IPartImportsSatisfiedNotification
 {
   private string name;
   public MyClass(string name)
   {
       this.name = name;
   }
 }

public interface IPartImportsSatisfiedNotification
    {
        void SomeMethod();
    }

    public abstract class MyClass : IDisposable, IPartImportsSatisfiedNotification
    {
        private string name;
        public MyClass(string name)
        {
            this.name = name;
        }

        public abstract void SomeMethod();

        public abstract void Dispose();
    }

    public class SubClass : MyClass
    {
        public SubClass(string someString) : base(someString)
        {

        }

        public override void SomeMethod()
        {
            throw new NotImplementedException();
        }

        public override void Dispose()
        {
            throw new NotImplementedException();
        }
    }

public abstract class MyClass : IDisposable, IPartImportsSatisfiedNotification
    {
        private string name;
        public MyClass(string name)
        {
            this.name = name;
        }

        public abstract void Dispose();
    }

public abstract void Dispose(); // implements IDisposable

void Main()
{
DerivedClass dc = new DerivedClass("hello, world");
Console.Out.WriteLine(dc);
string result = dc.Notify("greetings");
Console.Out.WriteLine(result);
}



public interface IPartImportsSatisfiedNotification
{
string Notify(string msg);
}



public abstract class MyClass  : IPartImportsSatisfiedNotification
{
   protected string name;
   public MyClass(string name)
   {
   this.name = name;
   }

   abstract public string Notify(string msg);

 }

 public class DerivedClass : MyClass
 {
public DerivedClass(string name) :base(name)
{

}

public override string Notify(string msg)
{
    return string.Format("Msg {0} from {1}", msg, this.name);
}

public override string ToString()
{
    return this.name;
}
 }