/// <summary>
        /// 修改某一项角色权限
        /// </summary>
        /// <param name="data"></param>
        public void ModifyRoleRight(RoleRight data)
        {
            if (data == null)
            {
                throw new Exception("角色权限不能为空。");
            }

            this.Entry <RoleRight>(data).State = System.Data.EntityState.Modified;
        }
        /// <summary>
        /// 删除一个角色权限
        /// </summary>
        /// <param name="data"></param>
        public void DeleteRoleRight(RoleRight data)
        {
            if (data == null)
            {
                throw new Exception("角色权限不能为空。");
            }

            //this.Set<RoleRight>().Remove(data);
            this.Entry <RoleRight>(data).State = System.Data.EntityState.Deleted;
        }
        /// <summary>
        /// 给角色增加一个权限,重新生成唯一标识
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public RoleRight AddRoleRight(RoleRight data)
        {
            if (data == null)
            {
                throw new Exception("角色权限信息不能为空。");
            }

            //data.RoleID = System.Guid.NewGuid().ToString();

            this.Set <RoleRight>().Add(data);

            return(data);
        }