/// <summary>
/// Determines if the current context has a stored item with given key.
/// </summary>
/// <param name="key">Key to look up.</param>
/// <returns>True if key exists in current context, false if not.</returns>
public bool HasKey(string key)
{
if (key.Length == 0)
{
throw new EmptyKeyException();
}
return(Items.ContainsKey(key));
}
