关于自己多次return的改写

 /// <summary>
        /// 修改政务公开目录
        /// </summary>
        /// <param name="tree_id">目录id</param>
        /// <param name="tree_name">目录名称</param>
        /// <param name="p_tree_id">上级目录id</param>
        /// <param name="depart_belong">所属部门分类</param>
        /// <param name="message">返回的提示消息</param>
        /// <returns></returns>
        public bool updateGovernmentOpenTree(long tree_id,string tree_name, long? p_tree_id, string depart_belong, out string message)
        {
            if (!IfCircle(tree_id, p_tree_id))
            {
                message = "出现目录的循环,请重新操作";
               return false;
            }
            if (IfParentNoHasChilren(depart_belong, tree_id))
            {
                message = "此目录下存在子目录的部门分类不包含在此目录中，逻辑错误，请重新操作";
                return false;
            }
            if (p_tree_id != null)
            {
                T_GOVERNMENT_AFFAIR_OPEN_TREE gaot = GetOneGovernmentTree(Convert.ToInt64(p_tree_id));
                if (gaot == null)
                {
                    message = "不存在此上级目录";
                    return false;
                }
                else
                {
                    if (IfNoHasString(gaot.DEPART_BELONG, depart_belong))//判断包含关系（如果不包含这些部门分类）
                    {
                        message = "上级目录的部门分类不包含此目录的所选分类，请重新操作";
                        return false;
                    }
                }
            }
            if (IfExistName(tree_name,tree_id))
            {
                message = "已经存在此政务公开目录名";
                return false;
            }
            T_GOVERNMENT_AFFAIR_OPEN_TREE governmenttree = db.T_GOVERNMENT_AFFAIR_OPEN_TREE.FirstOrDefault(g => g.TREE_ID == tree_id);
            governmenttree.TREE_NAME = tree_name;
            governmenttree.P_TREE_ID = p_tree_id;
            governmenttree.DEPART_BELONG = depart_belong;
            if (db.SaveSubmit())
            {
                message = "修改成功";
                return true;
            }
            else
            {
                message = "修改失败";
                return false;
            }
        }

 上面的代码多次return，代码可读性差，该应该改写如下:

            bool flag = true;
            if (!IfCircle(tree_id, p_tree_id))
            {
                message = "出现目录的循环,请重新操作";
                flag = false;
            }
            else
            {
                if (IfParentNoHasChilren(depart_belong, tree_id))
                {
                    message = "此目录下存在子目录的部门分类不包含在此目录中，逻辑错误，请重新操作";
                    flag = false;
                }
                else
                {
                    if (p_tree_id != null)
                    {
                        T_GOVERNMENT_AFFAIR_OPEN_TREE gaot = GetOneGovernmentTree(Convert.ToInt64(p_tree_id));
                        if (gaot == null)
                        {
                            message = "不存在此上级目录";
                            flag = false;
                        }
                        else
                        {
                            if (IfNoHasString(gaot.DEPART_BELONG, depart_belong))//判断包含关系（如果不包含这些部门分类）
                            {
                                message = "上级目录的部门分类不包含此目录的所选分类，请重新操作";
                                flag = false;
                            }
                        }
                    }
                    else
                    {
                        if (IfExistName(tree_name, tree_id))
                        {
                            message = "已经存在此政务公开目录名";
                            flag = false;
                        }
                        else
                        {
                            T_GOVERNMENT_AFFAIR_OPEN_TREE governmenttree = db.T_GOVERNMENT_AFFAIR_OPEN_TREE.FirstOrDefault(g => g.TREE_ID == tree_id);
                            governmenttree.TREE_NAME = tree_name;
                            governmenttree.P_TREE_ID = p_tree_id;
                            governmenttree.DEPART_BELONG = depart_belong;
                            if (db.SaveSubmit())
                            {
                                message = "修改成功";
                                flag = true;
                            }
                            else
                            {
                                message = "修改失败";
                                flag = false;
                            }
                        }
                    }
                }
            }
            return flag;