由多个接口得到一个接口

接口间可用:实现服用，如public interface IMovable : IDrivable, ISteerable，例如

/*
  Example8_6.cs illustrates deriving an
  interface from multiple interfaces
 */

using System;


// define the IDrivable interface
public interface IDrivable
{

  // method declarations
  void Start();
  void Stop();

  // property declaration
  bool Started
  {
    get;
  }

}


// define the ISteerable interface
public interface ISteerable
{

  // method declarations
  void TurnLeft();
  void TurnRight();

}


// define the IMovable interface (derived from IDrivable and ISteerable)
public interface IMovable : IDrivable, ISteerable
{

  // method declarations
  void Accelerate();
  void Brake();

}


// Car class implements the IMovable interface
public class Car : IMovable
{

  // declare the underlying field used by the
  // Started property of the IDrivable interface
  private bool started = false;

  // implement the Start() method of the IDrivable interface
  public void Start()
  {
    Console.WriteLine("car started");
    started = true;
  }

  // implement the Stop() methodof the IDrivable interface
  public void Stop()
  {
    Console.WriteLine("car stopped");
    started = false;
  }

  // implement the Started property of the IDrivable interface
  public bool Started
  {
    get
    {
      return started;
    }
  }

  // implement the TurnLeft() method of the ISteerable interface
  public void TurnLeft()
  {
    Console.WriteLine("car turning left");
  }
  
  // implement the TurnRight() method of the ISteerable interface
  public void TurnRight()
  {
    Console.WriteLine("car turning right");
  }

  // implement the Accelerate() method of the IMovable interface
  public void Accelerate()
  {
    Console.WriteLine("car accelerating");
  }
  
  // implement the Brake() method of the IMovable interface
  public void Brake()
  {
    Console.WriteLine("car braking");
  }

}


class Example8_6
{

  public static void Main()
  {

    // create a Car object
    Car myCar = new Car();

    // call myCar.Start()
    Console.WriteLine("Calling myCar.Start()");
    myCar.Start();

    // call myCar.TurnLeft()
    Console.WriteLine("Calling myCar.TurnLeft()");
    myCar.TurnLeft();

    // call myCar.Accelerate()
    Console.WriteLine("Calling myCar.Accelerate()");
    myCar.Accelerate();

  }

}