与装饰器模式类似，只继承接口；

示例代码：

interface IStudent
{
    public void GetInfo();
}
class Student : IStudent
{
    public void GetInfo()
    {
        Console.WriteLine("上小学中。。。");
    }
}
class ProxyStudent : IStudent
{
    private IStudent _student = new Student();
    public void GetInfo()
    {
        Console.WriteLine("小学之前4岁！");
        _student.GetInfo();
        Console.WriteLine("小学之后10岁！");
    }
}
class Pro
{
    public static void Main()
    {
        IStudent student = new Student();
        Console.WriteLine("-------------通常----------------");
        student.GetInfo();
        Console.WriteLine("-----------代理模式--------------");
        ProxyStudent proxyStudent = new ProxyStudent();
        proxyStudent.GetInfo();
    }
}