public bool DeleteUser(UsersInfo usersinfo,DataTable userstable)//删除数据表的方法,两个参数,一个是针对数据库,一个则是对内存中的DataTable
        {
            UsersInfo usersf = new UsersInfo();
            string commandText = "DELETE FROM Users WHERE 1=1 AND UserID=@userid";
            SqlParameter paramID = new SqlParameter("@userid",usersinfo.UserID);
            if(usersinfo.Note!="admin")
            {
            if (this.handler.Delete(commandText, new SqlParameter[] { paramID })>0)
            {
                    if (userstable!=null && userstable.Rows.Count > 0)
                    {
                        DataRow[] rows = userstable.Select("UserID" +usersinfo.UserID);
                        foreach (DataRow row in rows)
                        {
                            row.Delete();
                            return true;
                        }
                        userstable.AcceptChanges();//在删除时对内存中的DataTable表进行
                    }
                    return true;
            }
            }
            return false;
        }