How to compare two time values in C#-CodePudding

I want to compare two times in C# and want to make sure that the end time is later than the start time. The following is my code.

string startTime = "02:25 PM";
string endTime = "02:30 PM";
TimeSpan startTime = TimeSpan.Parse(StartTime);
TimeSpan endTime = TimeSpan.Parse(EndTime);
int timeDifference = startTime.CompareTo(endTime);
if (timeDifference.Equals(0) || timeDifference.Equals(-1))
{
  errMessage.Append("The end time has to be greater than the start time. <br />");
}

The above code doesn't work as TimeSpan.Parse() throws an error as it can't handle the "PM" in the time value.

CodePudding user response：

If you want to do it with TimeSpans you'll have to handle the PM:

TimeSpan startTime = TimeSpan.Parse(StartTime.Remove(5));
TimeSpan endTime = TimeSpan.Parse(EndTime.Remove(5));

if(StartTime.Contains("PM"))
  startTime = startTime   TimeSpan.FromHours(12);
if(EndTime.Contains("PM"))
  endTime = endTime   TimeSpan.FromHours(12);

^{If your PM will vary in case, use an overload of Contains that can be case insens}

Or you can get DateTime to do your parsing:

var startTime = DateTime.ParseExact(StartTime, "hh:mm tt", CultureInfo.InvariantCulture).TimeOfDay;
var endTime = DateTime.ParseExact(EndTime, "hh:mm tt", CultureInfo.InvariantCulture).TimeOfDay;

TimeSpans are a lot like numbers and are hence comparable with things like <, >= etc so you can just do:

if(startTime < endTime)
  errMessage.Append("The end time has to be greater than the start time. <br />");