public static int GetTeacherRenke_min_kechengid(string teacherusername)//得到教师任课的最小课程id
    {
        DataTable dt = RenkeInfo.GetTeacherRenKeKecheng(teacherusername);

        if (dt.Rows.Count > 0)
        {
            return(Convert.ToInt32(dt.Rows[0][1]));
        }
        else
        {
            return(-1);
        }
    }