Question

My Class Structure is Like This.

Class A
{
}

Class B:A{..}

Class Demo
    {
    //Here Actual Parameter is instance of Class B. But in xyz function accepts
    //  parameter of type Class A. So in Below function can i get the Properties of 
    //Class B by using "((B)a).Property_Name", But i don want to specify the Name 
    //of Class B. So is ther any approach to meet my need.
    public void xyz(A a){ ....Here I Can i get }
    }

Answer 1

It sounds like you want to use a member of B that doesn’t exist in A in a method that takes in A as a parameter. You don’t want to move the member to A because it probably does’t make sense to do so and you want something special when a B is passed in.

The most straight forward way is to test for it

public void xyz(A a){


     if (a is B) 
     {
          ((B)a).dosomthing()
     } 

 }

However this is bad because maybe you have C that needs this to.

Then maybe its better to introduce an interface e.g.

B: A, ISomthing

public void xyz(A a){


     if (a is ISomthing) 
     {
          ((ISomthing)b)dosomthing()
     } 

 }

Another option is to use Double Dispatch