C#中增强类功能的几种方式详解

namespace Decorator
{

 /// <summary>
 /// Component 抽象者装饰者
 /// </summary>
 public interface IStudent
 {
  void Learn();
 }

 /// <summary>
 /// ConcreteComponent 具体被装饰者
 /// </summary>
 public class Student : IStudent
 {
  private string _name;
  public Student(string name)
  {
   this._name = name;
  }
  public void Learn()
  {
   System.Console.WriteLine(this._name + "学习了以上内容");
  }
 }
 /// <summary>
 /// Decorator 装饰者
 /// </summary>
 public abstract class Teacher : IStudent
 {
  private IStudent _student;
  public Teacher(IStudent student)
  {
   this._student = student;
  }
  public virtual void Learn()
  {
   this.Rest();
   this._student.Learn();
  }

  public virtual void Rest()
  {
   Console.WriteLine("课间休息");
  }
 }

 /// <summary>
 /// ConcreteDecorator 具体装饰者
 /// </summary>
 public class MathTeacher : Teacher
 {
  private String _course;
  public MathTeacher(IStudent student, string course) : base(student)
  {
   this._course = course;
  }
  public override void Learn()
  {
   System.Console.WriteLine("学习新内容：" + this._course);
   base.Learn();
  }
  public override void Rest()
  {
   System.Console.WriteLine("课间不休息，开始考试");
  }
 }

 /// <summary>
 /// ConcreteDecorator 具体装饰者
 /// </summary>
 public class EnlishTeacher : Teacher
 {
  private String _course;
  public EnlishTeacher(IStudent student, string course) : base(student)
  {
   this._course = course;
  }

  public override void Learn()
  {
   this.Review();
   System.Console.WriteLine("学习新内容：" + this._course);
   base.Learn();
  }

  public void Review()
  {
   System.Console.WriteLine("复习英文单词");
  }
 }

 public class Program
 {
  static void Main(string[] args)
  {
   IStudent student = new Student("student");
   student = new MathTeacher(student, "高数");
   student = new EnlishTeacher(student, "英语");
   student.Learn();
  }
 }
}