ADO Database C#

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.OleDb;
class MainClass {
    public static void Main() {
        using (SqlConnection con = new SqlConnection()) {
            con.ConnectionString = @"Data Source=.\sqlexpress;Database=Northwind;Integrated Security=SSPI";    
            con.Open();
            if (con.State == ConnectionState.Open) {
                Console.WriteLine("  Packet Size = " + con.PacketSize);
            } else {
                Console.WriteLine("SqlConnection failed to open.");
                Console.WriteLine("  Connection State = " + con.State);
            }
        }
    }
}