在for循环中创建类构造函数

Question

在循环中创建类是好的编码方法吗？也就是说，我正在调用数据库以检索所有联系人，在此循环中，我基于联系人ID创建了联系人类（该类再次调用DB以基于ID检索联系人详细信息）。这是智能编码还是浪费资源？

MySqlDataReader reader = command.ExecuteReader();
while (reader.Read()) {
    Contact contact = new Contact(Convert.ToInt32(reader["contactid"]));
    userString = userString + contact.getSurname();
}

public Contact(int id) {
    MySqlConnection connection = new MySqlConnection(Global.conn);
    connection.Open();
    MySqlCommand command = connection.CreateCommand();
    string sql = "SELECT * 
                    FROM contact 
                  WHERE contactid=@contactid";
    command.CommandText = sql;
    command.Parameters.AddWithValue("@contactid", id);
    MySqlDataReader reader = command.ExecuteReader();
    while (reader.Read()) {
        FirstName = reader["name"].ToString();
        Surname = reader["Surname"].ToString();
    }
}