How to compare string "203658.000" to UTC in C#?

Question

I have a string "203658.000" which encodes UTC time from a GPS receiver.

The format is "hhmmss.ffff", where:

• "hh" is hours (fixed two digits)
• "mm" is minutes (fixed two digits)
• "ss" is seconds (fixed two digits)
• "fff" is decimal fraction of seconds (variable length)

I'd like to know if the time is correct. To do that, I think I should convert the string to a DateTime, then compare it to DateTime.UtcNow.

Here is my code so far:

int timestamp = (int)Convert.ToDouble("203658.000");
int hours = (timestamp % 1000000 - timestamp % 10000) / 10000;
int minutes = (timestamp % 10000 - timestamp % 100) / 100;
int seconds =  timestamp % 100;

DateTime dateTime = new DateTime(DateTime.UtcNow.Year, DateTime.UtcNow.Month, DateTime.UtcNow.Day, hours, minutes, seconds);

if (DateTime.UtcNow.Equals(dateTime))
{
    // Pass
}

Is there a TryParse method to do this instead of extracting hours, minutes, and seconds mathematically?

Answer 1

You should be able to use DateTime.ParseExact to get what you need.

DateTime.ParseExact("203658.000", "HHmmss.fff", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal)

Be careful around midnight though, as the time could be nearly 24 hours out if the dates don't match.