C# marking member as "do not use"

Question

public class Demo {     private List<string> _items;     private List<string> Items     {         get         {             if (_items == null)                 _items = ExpensiveOperation();              return _items;         }     } } 

Other methods in the Demo class will have access to the _items field. Since I'm using a property to lazy load the items, I do not want another developer to mistakenly try to use the _items field.

I know there is the ObsoleteAttribute that I may use, but this field isn't technically obsolete.

Is there a better way to mark a member as "do not use"?

Answer 1

Though it's not a general technique for what you want to do (and there isn't one and, as the other answers cover, you need to trust other devs), in this instance, you could create a Lazy<List<T>> (assuming .NET 4 or later - though it's easy to backport)

class Demo {     readonly Lazy<List<string>> _items;     public Demo() {         var _items = new Lazy<List<string>>( ExpensiveOperation);     }     List<string> Items { get { return _items.Value; }}  } 

The readonly / non-mutable approach is generally the way to go for backing fields either way.

EDIT: Based on @Timwi's answer (go +1 if you like the idea) one can go to town on it, and in a JavaScript stylee use capability-based restriction to not even expose the Lazy field, just an operation closed over it (Also incorporates @Mr Disappointment's ReadOnlyCollection suggestion):

class Demo {     readonly Func<ReadOnlyCollection<string>> _getItems;     public Demo() {         var items = new Lazy<List<string>>( ExpensiveOperation);         _getItems = () => items.Value.AsReadOnly();     }     ReadOnlyCollection<string> Items { get { return _getItems(); }}  } 

And thus endeth our stupid coding tricks post.