IteratorContainer_Class.cs

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using System.Collections.Generic;
 
namespace DesignPatternExamples_csharp
{
    public class ItemPair
    {
        public string Key;
        public string Value;
 
        public ItemPair(string key, string value)
        {
            Key = key;
            Value = value;
        }
    }
 
 
    public interface IIterator<TItemType>
    {
        void Reset();
    
        TItemType? Next();
    }
 
 
    class Iterator<TItemType> : IIterator<TItemType>
    {
        TItemType[] _items;
 
        int _index;
 
        public Iterator(TItemType[] items)
        {
            _items = (TItemType[])items.Clone();
        }
 
        public TItemType? Next()
        {
            TItemType? item = default(TItemType);
 
            if (_index < _items.Length)
            {
                item = _items[_index];
                ++_index;
            }
            return item;
        }
 
        public void Reset()
        {
            _index = 0;
        }
    }
 
 
    public class IteratorContainer_Class
    {
        // Hardcoded data to be iterated over.
        // The number of keys must match the number of values.
        // This container is not a dictionary despite the use of Keys and
        // Values as names but it was the simplest form of data I could come
        // up with that didn't use any of the C# containers.
        string[] _keys = new string[] { "One", "Two", "Three" };
        string[] _values = new string[] { "Value 1", "Value 2", "Value 3" };
 
        public IIterator<ItemPair> GetItems()
        {
            List<ItemPair> items = new List<ItemPair>();
 
            int numItems = _keys.Length;
            for (int index = 0; index < numItems; ++index)
            {
                items.Add(new ItemPair(_keys[index], _values[index]));
            }
 
            // Note: the ToArray() creates a copy of the list but as an
            // array.
            return new Iterator<ItemPair>(items.ToArray());
        }
 
        public IIterator<string> GetKeys()
        {
            return new Iterator<string>(_keys);
        }
 
        public IIterator<string> GetValues()
        {
            return new Iterator<string>(_values);
        }
    }
}