Returning readonly version of object

Hello,

Need urgent help. Hope for good solution.

I have two classes inherited from System.Collections.CollectionBase.

Code:

---

public class1: System.Collections.CollectionBase
{ //.. }

public class2: System.Collections.CollectionBase
{

    private class1 obj = new class1();

    public class1 MyReadOnlySubClass
    {
          get { return class1; }
    }

    //..
}

---

So I return class1 as property in class2. How to hide returned class'es methods such Add, Clear, Insert, RemoveAt? I only need ability to enumerate this class with foreach and get all child objects.


Regards in advance,
Andrius

Also I think there may be same problem with class1's inner object collections.

If I could return readonly version of class1 in class2, then calling to inner object of this returned class, they would be read-write, not read-only.