//a callback method used to receive new log entries from ATMs and update logs
private void updateLog(string logEntry)
{
log.Add(DateTime.Now.ToString("hh:mm:ss") + " - " + logEntry);
BankAccounts.Invoke(new MethodInvoker(delegate
{
BankAccounts.DataSource = null;
BankAccounts.DataSource = log;
}));
}