using System.Web.Mvc;
using Oracle.ManagedDataAccess.Client;

string oradb = "Data Source=WorkTest;User Id=C##;Password=123;";
            OracleConnection conn = new OracleConnection(oradb);  // C#
            conn.Open();
            OracleCommand cmd = new OracleCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from ааа";
            cmd.CommandType = CommandType.Text;
            OracleDataReader dr = cmd.ExecuteReader();
            dr.Read();
            var cc = dr.GetString(0);
            conn.Dispose();

# tnsnames.ora Network Configuration File: D:\app\username\product\12.1.0\dbhome_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

LISTENER_WORKTEST =
  (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))

ORACLR_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
    (CONNECT_DATA =
      (SID = CLRExtProc)
      (PRESENTATION = RO)
    )
  )

LISTENER_ORCL =
  (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))

WORKTEST =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = WorkTest)
    )
  )

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )