/// <summary>
/// Get first (chronologically) descendant at the specified level
/// </summary>
/// <param name="level">
/// Level at which to find descendant. Must point to a descendant (i.e. be less than <code>this.Level</code> and greater or
/// equal to zero (which is leaf level).
/// </param>
/// <param name="backwards">
/// Whether to find oldest (<see langword="false"/>) or newest (<see langword="true"/>) descendant.
/// </param>
/// <returns>
/// First descendant at <paramref name="level"/> or <see langword="null"/> if none exists.
/// </returns>
public IDataFolder GetFirstDescendant(int level, bool backwards)
{
RequireDescendant(level);
IDataFolder descendant = GetFirstChildFolder(backwards);
if (descendant != null && level < (this.Level - 1))
{
descendant = descendant.GetFirstDescendant(level, backwards);
}
else if (level == (this.Level - 1))
{
// reached target level
return(descendant);
}
return(null);
}
