这是我的班级,我不希望在子班级中覆盖此方法,我该如何完成这种行为?
class A 
{ 
   public virtual void demo() 
   { 
   } 
} 
class B : A 
{ 
   public override void demo() 
   { 
   } 
} 
// when Class B be inherited in C, methods can be overridden further, 
// but I don't want the method to be overridden further.
class C : B 
{ 
}