查询MySQL DB

public DataTable ConnMySql(string strRegisterNo)
        {
            try
            {
                DataTable dt = new DataTable("table");
                string constr = IP"server=.;database=DB;uid=sa; pwd=sa";
                string sql = "select * from tablename where ID= ‘"   strNo   "‘";

                SqlDataAdapter adptr = new SqlDataAdapter(sql, constr);
                adptr.Fill(dt);
                return dt;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }