过程函数和抽象派生类中的变量

如何避免来自任何派生类的问题并编写两次代码？

我尝试过以下几种：

Type t = GetType(obj); 
(obj as t).health

通过这样做，Visual Sudio说health is not member of... blah

这是我的代码：

// gameobjects-class    
abstract gameobject
{
Vector2 Position
void update()
etc...

class meteor : gameobject
{
float rotation
etc...
class player : gameobject
{
int health, attackpower
etc...
class enemy: gameobject
{
int health, attackpower
etc...

从GameObject 访问数据的外部类

class anyclass
{
void checkhealth(gameobject obj)   // QUESTION:
{
if (obj as player).health = 0      // 
     kill(obj)                     // 
if (obj as enemy).health = 0       // 
     kill(obj)                     // 

有什么建议吗？谢谢

interface ILivingGameObject
{
    int Health {get;set;}
}
class Player : GameObject, ILivingGameObject
{
}
void CheckHealth(ILivingGameObject obj)
{
     if(obj.Health == 0)
          kill(obj);
}

class LivingObject : GameObject
{
    int Health {get;set;}
}
class Player : LivingObject
{
}
void CheckHealth(LivingObject obj)
{
}