ComponentCollection.cs

using System;
using System.Collections.Generic;

namespace ScriptingTestingGrounds
{
	public class ComponentCollection : ICollection<IGameComponent>
	{
		private IDictionary<Type, IGameComponent> dict =
			new Dictionary<Type, IGameComponent>();

		public GameEntity Entity { get; private set; }

		public int Count { get { dict.Count; } }
		public bool IsReadOnly { get { return false; } }

		public event Action<IGameComponent> OnAdded;
		public event Action<IGameComponent> OnRemoved;

		public ComponentCollection(GameEntity entity)
		{
			Entity = entity;
		}

		public T Get<T>()
		{
			T component = null;
			dict.TryGetValue(typeof(T), out component);
			return component;
		}

		#region ICollection implementation

		public void Add(IGameComponent component)
		{
			dict.Add(component.GetType(), component);
			if (OnAdded != null)
				OnAdded(component);
		}

		public bool Remove(IGameComponent component)
		{
			if (dict.Remove(component.GetType())) {
				if (OnRemoved != null)
					OnRemoved(component);
				return true;
			} else return false;
		}

		public void Clear()
		{
			if (OnRemoved != null) {
				IList<IGameComponent> list = new List<IGameComponent>(dict.Values);
				dict.Clear();
				foreach (IGameComponent component in list)
					OnRemoved(component);
			} else dict.Clear();
		}

		public bool Contains(IGameComponent component)
		{
			dict.ContainsKey(component.GetType());
		}

		public void CopyTo(IGameComponent[] array, int arrayIndex)
		{
			dict.Values.CopyTo(array, arrayIndex);
		}

		#endregion

		#region IEnumerable implementation

		public IEnumerator<IGameComponent> GetEnumerator()
		{
			return dict.Values.GetEnumerator();
		}

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

		#endregion
	}
}

GameEntity.cs

using System;
using System.Collections.Generic;

namespace ScriptingTestingGrounds
{
	public class GameEntity
	{
		public Guid ID { get; internal set; }
		public ComponentCollection Components { get; private set; }

		public GameEntity()
		{
			Components = new ComponentCollection(this);
		}
	}
}