string connstr = "data source=orcl;User Id =scott;Password =tiger";
            OracleConnection conn = new OracleConnection(connstr);
            conn.Open();
            string sql = "select * from emp";
            OracleCommand commd = new OracleCommand(sql,conn);
            OracleDataAdapter adpter = new OracleDataAdapter(commd);
            DataTable table = new DataTable();
            adpter.Fill(table);
            dataGridView1.DataSource = table;
 

忘記conn.Open() 一直提示無效操作，連線關閉。以後要注意了，基本的東西不能忘呀。。。。。。。