/// <summary>
    /// Gets the list of users in this group.
    /// </summary>
    /// <returns>The users list.</returns>
    public List <Person> GetUsersList()
    {
        if (userGroupId != initedGroupId)
        {
            GetOrGreateUserGroup();
        }
        if (userGroupId != initedGroupId)
        {
            return(null);
        }

        if (faceManager != null && !string.IsNullOrEmpty(userGroupId))
        {
            Person[] persons = faceManager.ListPersonsInGroup(userGroupId);

            if (persons != null)
            {
                return(new List <Person>(persons));
            }
        }

        return(null);
    }