public static void PersistToDisk()
{
if (allTrips != null)
{
string datafilename = Path.Combine(Util.DocDir, "triplog.txt");
if (File.Exists(datafilename))
File.Delete(datafilename);
List<string> lines = new List<string>();
foreach(var trip in allTrips)
{
lines.Add(trip.AsLine);
}
File.WriteAllLines(datafilename, lines.ToArray());
}
}