Connection string in DBContext

I want to add connection string in dbcontext file not in App config file because of security and multiple databases.i m using npgsql (.net provider for postgresql database). here is my coding.

 public partial class ADBEntities : DbContext
    {
        public ADBEntities()
        {
            Npgsql.NpgsqlConnectionStringBuilder ssb = new NpgsqlConnectionStringBuilder();
            ssb.Host = "localhost";
            //ssb.Port = 5432;
            ssb.UserName = "postgres";
            ssb.Password = "a5xxx";
            ssb.Database = "adb";
            ssb.CommandTimeout = 30;
            ssb.Pooling = true;
            ssb.MaxPoolSize = 20;
            ssb.MinPoolSize = 1;
            ssb.PreloadReader = true;
            ssb.IntegratedSecurity = true;

            var cond= new NpgsqlConnection(ssb);
            this.Database.Connection.ConnectionString = cond.ConnectionString;
        }
}

But it is not working and giving error "Keyword "Port" is not supported.