我做了一个。net小程序。用的是sql数据库。但是有些数据只能在另一个服务器上的Sybase数据库上取。所以我写了一段连接Sybase的代码。但是报错。求各位大神赐教
 AseConnection con = new AseConnection();
             con = new AseConnection("Data Source=115.238.39.90;Port=5000;database=drms;User id=sa;Password=123321;");
             con.Open();
             AseCommand da = new AseCommand("select * from pos.p_inv where piv_br_id = 0001 and piv_date = 2013-05-23", con);
 AseDataReader dr = da.ExecuteReader();
             FileStream fs = new FileStream("D:\\2.txt", FileMode.Open);
             StreamWriter sw = new StreamWriter(fs, Encoding.Default);
             while (dr.Read())
             {
                 string a1 = dr.GetString(dr.GetOrdinal("piv_bill_no"));
                 string a2 = dr.GetString(dr.GetOrdinal("piv_br_id"));
                 DateTime a3 = dr.GetDateTime(dr.GetOrdinal("piv_date"));
                 string a4 = dr.GetString(dr.GetOrdinal("piv_time"));
                 string a5 = dr.GetString(dr.GetOrdinal("piv_emp"));
                 decimal a6 = dr.GetDecimal(dr.GetOrdinal("piv_zk_amt"));
             }
string str = a1.ToString() + "," + a2.ToString() + "," + a3.ToString() + "," + a4.ToString() + "," + a5.ToString() + "," + a6.ToString();
 dr.Close();
            con.Close();
这段代码编译是成功的。但是运行就报错。。.NETSybase服务器数据库String