Accessing a property of derived class from the base class in C#

Question

In C#, what is the best way to access a property of the derived class when the generic list contains just the base class.

public class ClassA : BaseClass
{
          


        

Answer 1

   BaseClass o = MyList[i];
   if (o is ClassB)
   {
      object k = ((ClassB)o).PropertyB;
   }
   if (o is ClassA))
   {
      object j = ((ClassA)o).PropertyA;
   }