類的繼承，大家試試看，想得是否和結果對得上。

virtual+override:

using System;
using System.Collections.Generic;
using System.Text;

namespace Leezile.LearningCS.Derived
...{
    class Program
    ...{
        static void Main(string[] args)
        ...{
            Building bb = new Building();
            Building ba = new BuildingA();
            BuildingA aa = new BuildingA();
            bb.Calculate();
            ba.Calculate();
            aa.Calculate();
        }
    }
    public class Building
    ...{
        public Building() //構造函數
        ...{
            Console.WriteLine("Create class Building");
        }
        public virtual void Calculate() 
        ...{
            Console.WriteLine("Building Calculate");
        }
    }
    public class BuildingA:Building
    ...{
        public BuildingA() //構造函數
        ...{
            Console.WriteLine("Create class BuildingA");
        }
        public override void Calculate()
        ...{
            Console.WriteLine("BuildingA Calculate");
        }
    }
}

 結果： 

Create class Building
Create class Building
Create class BuildingA
Create class Building
Create class BuildingA
Building Calculate
BuildingA Calculate
BuildingA Calculate

 

abstract+override:

using System;
using System.Collections.Generic;
using System.Text;

namespace Leezile.LearningCS.Derived
...{
    class Program
    ...{
        static void Main(string[] args)
        ...{
            //Building bb = new Building(); //抽象函數不能實例化
            Building ba = new BuildingA();
            BuildingA aa = new BuildingA();
            //bb.Calculate();
            ba.Calculate();
            aa.Calculate();
        }
    }
    public abstract class Building
    ...{
        public Building() //構造函數
        ...{
            Console.WriteLine("Create class Building");
        }
        public abstract void Calculate();
    }
    public class BuildingA : Building
    ...{
        public BuildingA() //構造函數
        ...{
            Console.WriteLine("Create class BuildingA");
        }
        public override void Calculate()
        ...{
            Console.WriteLine("BuildingA Calculate");
        }
    }
}

 

結果：

Create class Building
Create class BuildingA
Create class Building
Create class BuildingA
BuildingA Calculate
BuildingA Calculate

 

_+new:

using System;
using System.Collections.Generic;
using System.Text;

namespace Leezile.LearningCS.Derived
......{
    class Program
    ......{
        static void Main(string[] args)
        ......{
            Building bb = new Building();
            Building ba = new BuildingA();
            BuildingA aa = new BuildingA();
            bb.Calculate();
            ba.Calculate();
            aa.Calculate();
        }
    }
    public class Building
    ......{
        public Building() //構造函數
        ......{
            Console.WriteLine("Create class Building");
        }
        public void Calculate() 
        ......{
            Console.WriteLine("Building Calculate");
        }
    }
    public class BuildingA:Building
    ......{
        public BuildingA() //構造函數
        ......{
            Console.WriteLine("Create class BuildingA");
        }
        public new void Calculate() //這裏用不用new也是一樣，只是隱藏了基類的方法，但沒有顯式聲明
        ......{
            Console.WriteLine("BuildingA Calculate");
        }
    }
}

結果：

Create class Building
Create class Building
Create class BuildingA
Create class Building
Create class BuildingA
Building Calculate
Building Calculate
BuildingA Calculate