Question

How to implement IEnumerator on this class so that I can use it in foreach loop.

public class Items
    {
        private Dictionary<string, Configuration> _items = new Dictionary<string, Configuration>();

        public Configuration this[string element]
        {
            get
            {

                if (_items.ContainsKey(element))
                {
                    return _items[element];
                }
                else
                {
                    return null;
                }
            }

            set
            {
                _items[element] = value;
            }
        }
   }

In this example Configuration is a simple class with few properties.

Answer 1

Just an example to implement typesafe IEnumerable and not IEnumerator which you will be able to use in foreach loop.

   public class Items : IEnumerable<Configuration>
    {
        private Dictionary<string, Configuration> _items = new Dictionary<string, Configuration>();


        public void Add(string element, Configuration config) {
            _items[element] = config;
        }

        public Configuration this[string element]
        {
            get
            {

                if (_items.ContainsKey(element))
                {
                    return _items[element];
                }
                else
                {
                    return null;
                }
            }

            set
            {
                _items[element] = value;
            }
        }

        public IEnumerator<Configuration> GetEnumerator()
        {
            return _items.Values.GetEnumerator();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return _items.Values.GetEnumerator();
        }
    }

Regards.