//好友在不在分组中,在,返回该好友,不在,添加新的好友,返回该好友
        public static FriendEntity InGroupAdd(ref FriendGroup friendGroup, String name)
        {
            foreach (var entity in friendGroup.Friends)
            {
                if (entity.Name == name)
                {
                    return(entity);
                }
            }
            FriendEntity friendentity = new FriendEntity();

            friendGroup.FriendGroupAdd(ref friendentity);
            return(friendentity);
        }
        //检查指定名字的分组是否在分组列表中,如果在分组List中,返回该分组,如果不在,添加一个分组并返回该分组
        public static FriendGroup InGroupListAdd(ref ObservableCollection <FriendGroup> grouplist, String name)
        {
            foreach (var group in grouplist)
            {
                if (group.Name == name)
                {
                    return(group);
                }
            }
            FriendGroup friendGroup = new FriendGroup()
            {
                Name = name
            };

            grouplist.Add(friendGroup);
            return(friendGroup);
        }
        //从整个好友列表中删除对应的对象
        public static void InGroupListDelete(ObservableCollection <FriendGroup> friendGroups, String id)
        {
            FriendGroup  friendGroup  = null;
            FriendEntity friendEntity = null;

            foreach (var group in friendGroups)
            {
                foreach (var entity in group.Friends)
                {
                    if (entity.Id == id)
                    {
                        friendGroup  = group;
                        friendEntity = entity;
                        break;
                    }
                }
            }
            //删除对应的对象
            friendGroup.Friends.Remove(friendEntity);
            if (friendGroup.Friends.Count == 0)
            {
                friendGroups.Remove(friendGroup);
            }
        }