/// <summary>
/// Returns the key-value pair at the specified index in the ordered map, by key order.
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
/// <exception cref="ArgumentOutOfRangeException">If the index is out of range</exception>
public KeyValuePair <TKey, TValue> ByOrder(int index)
{
index.CheckIsBetween("index", -Root.Count, Root.Count - 1);
index = index < 0 ? index + Root.Count : index;
var opt = Root.ByOrder(index);
return(Kvp.Of(opt.Key, opt.Value));
}
/// <summary>
/// Returns the element at the specified position in the sort order.
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
public T ByOrder(int index)
{
index.CheckIsBetween("index", -Length, Length - 1);
index = index < 0 ? index + Length : index;
return(Root.ByOrder(index).Key);
}