“Read only” Property Accessor in C#

Question

I have the following class:

class SampleClass
{
   private ArrayList mMyList;

   SampleClass()
   {
       // Initialize mMyList
   }

   public ArrayList MyLis         


        

Answer 1

You should wrap the return value in a read only collection.

Answer 2

Use the ArrayList.ReadOnly() method to construct and return a read-only wrapper around the list. it won't copy the list, but simply make a read-only wrapper around it. In order to get compile-time checking, you probably want to return the read-only wrapper as IEnumerable as @Jared suggests.

public IEnumerable MyList
{
     get { return ArrayList.ReadOnly(mMyList); }
}

A collection that is read-only is simply a collection with a wrapper that prevents modifying the collection. If changes are made to the underlying collection, the read-only collection reflects those changes.

This method is an O(1) operation.

Reference