Question

I have created a class say A which has some functions defined as protected.

Now Class B inherits A and class C inherits B. Class A has private default constructor and protected parameterized constructor.

I want Class B to be able to access all the protected functions defined in Class A but class C can have access on some of the functions only not all the functions and class C is inheriting class B.

How can I restrict access to some of the functions of Class A from Class C ?

EDIT:

namespace Db
{
 public class A
  {
  private A(){}
  protected A(string con){assign this value}

  protected DataTable getTable(){return Table;}
  protected Sqlparameters setParameters(){return parameter;}
  }
}

namespace Data
{
 public class B:A
  {
  protected B():base("constring"){}

  protected DataTable output(){return getTable();}
  protected sqlparameter values(param IDataParameter[] parameter){}
  }
}

namespace Bsns
{
 public class C:B
  {
  protected C():base(){}

  protected DataTable show()
     {return values(setparameter());}

  }
}

EDIT

I think what I am trying to do here is Multiple inheritance.

Please check.

class A
{
//suppose 10 functions are declared 
}

class B:A
{
//5 functions declared which are using A's function in internal body
}


class C:B
{
//using all functions of B but require only 4 functions of A to be accessible by C.
}

Answer 1

I’d suggest that you rethink your design. Maybe there is a simpler way. What if C uses an instance of B instead of deriving from it (composition) ? That way C can use B’s public methods but not get access to the protected ones.

Class A should not care about the level/depth of a descendant. If something is marked protected, it should be protected for both B and C (regardless of the depth of the inheritance chain).
B may choose to delimit its descendants by tightening the constraints (but this is rare).

If you can tell me more about your context – the problem you are trying to solve.. I can give you a more detailed/useful answer.