class A
{
  public virtual void Show(){ Console.Write("this is "); }
}

class B:A
{
  public override void Show(){
     base.Show();
     Console.Write("a demo");

  }
}

------解决方案--------------------
一楼正解！

------解决方案--------------------
探讨


C# code


class A
{
  public virtual void Show(){ Console.Write("this is "); }
}

class B:A
{
  public override void Show(){
     base.Show();
     Console.Write("a demo");

  }
}


------解决方案--------------------
探讨


引用:

C# code


class A
{
public virtual void Show(){ Console.Write("this is "); }
}

class B:A
{
public override void Show(){
base.Show();
Console.Write("a demo");

}
}

+……