To  get this stuff you need to create a Ref Cursor to return recordset.

             create or replace PACKAGE Types AS

            TYPE cursor_type IS REF CURSOR;

Now create a stored procedure to return multiple rows .

           create or replace

           PROCEDURE getAllCity(p_recordset OUT types.cursor_type) AS

           BEGIN

           OPEN p_recordset FOR

           select * from tbl_country;

Now put this code in your event.

            string strconn =  myDynconnStr;

            OracleConnection conn = new OracleConnection(strconn);

            OracleCommand objCmd = new OracleCommand();

            objCmd.Connection = conn;

            objCmd.CommandText = "getAllCity";

            objCmd.CommandType = CommandType.StoredProcedure;

            objCmd.Parameters.Add("p_recordset", OracleType.Cursor).Direction = ParameterDirection.Output;

            OracleDataAdapter odr = new OracleDataAdapter(objCmd);

            DataSet ds = new DataSet();

            odr.Fill(ds);

            GridView1.DataSource = ds.Tables[0];

            GridView1.DataBind();