Question

If I create a private nested class, how can I access the variables and methods from the calling class?

Example:

   public class ClassA
   {
      protected int MyVar=100;

      public MethodA()
      {
         // <some code>
         myObjectClassB.DoSomething(); 
         // <some code>
      }

      private class ClassB
      {
         public DoSomething()
         {
         }
      }
   }

In the above example I need ClassB to be able to access ClassA.MyVar – Is this possible?

Answer 1

When you construct an instance of ClassB, give it a reference to the ClassA that owns it.

  private class ClassB
  {
     private readonly ClassA _owner;

     public ClassB(ClassA owner)
     {
          _owner = owner;
     }

     public DoSomething()
     {
     }
  }

One interesting thing to note about this is that the private nested class can actually access private members of ClassA through _owner. This often comes in handy when you have an internal helper class that needs access to the overall private state of the class.