Handle negative time spans

Admin 1
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In my output of a grid, I calculate a TimeSpan and take its TotalHours. e.g.

(Eval("WorkedHours") - Eval("BadgedHours")).TotalHours

The goal is to show the TotalHours as 39:44, so I need to convert the value from 7.5 to 07:30. This is no problem... unless it's negative!

I can create a TimeSpan object from Hours with 

TimeSpan.FromHours( (Eval("WorkedHours") - Eval("BadgedHours")).TotalHours)

If it's negative, I can't convert it to a DateTime to use the .ToString("HH:mm") method, and the TimeSpan object does not support the format string.

timespan datetime .net c#
9 Answers
static string ToHMString(TimeSpan timespan) { 
    if (timespan.Ticks < 0) return "-" + ToHMString(timespan.Negate());

    return timespan.TotalHours.ToString("#0") + ":" + timespan.Minutes.ToString("00");
}

Console.WriteLine(ToHMString(TimeSpan.FromHours(3)));       //Prints "3:00"
Console.WriteLine(ToHMString(TimeSpan.FromHours(-27.75)));  //Prints "-28:45"

This will also work correctly if the timespan is longer than 24 hours.

user_343970

Just multiply it by -1 or use an absolute value function.

user_235280

The simple solution would be to do:

string format = "HH:mm";
if(hours < 0)
  format = "-" + format;

hours = Math.Abs(hours)
user_253300 
TimeSpan Diff = Date1 - Date2;

if ((int)Diff.TotalDays < 0) { // your code }
user_116851480
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