How do I calculate the difference of times from three text boxes?

Question

I have three text boxes where I can enter time like on this screenshot:

Form screenshot

Finally I want to get the difference of entry time (t1), exit time (t2) and break (t3): t1 - t2 - t3.

But I am not able to do that because of error message:

Operator '-' cannot be applied to operands of type 'System.TimeSpan' and 'System.DateTime'

My code is as follows:

DateTime t1, t2, t3,  reserve;
t1 = DateTime.Parse(inBox.Text); //from text box1 eg.11:30
t2 = DateTime.Parse(outBox.Text); //from text box2 eg.12:30
t3 = DateTime.Parse(breakBox.Text); //from text box3 eg.0:30
TimeSpan diffTime = t2 - t1 -t3;// there is a problem doing this!!!
answerLabel.Text = diffTime.ToString();

Is DateTime really the way you want to go with this? You would be better using TimeSpan throughout as far as I can see. — KingCronus, Dec 21 '14 at 16:00
Operator '-' cannot be applied to operands of type 'System.TimeSpan' and 'System.DateTime' — Supermankid, Dec 21 '14 at 16:03
If you have additional information that goes with your question, edit the question to include that information instead of giving us links. — hatchet - done with SOverflow, Dec 21 '14 at 16:09
What would that mean in practice? Your wall clock can show 12, 10 and 6 o'clock. What is 12 - 10 - 6 supposed to mean? -4 is of course nonsense, avoid doing nonsensical things and your compiler will not tell you it is nonsense. — Hans Passant, Dec 21 '14 at 16:17
possible duplicate of [Hours elapsed between two times, irrespective of country and time zones](http://stackoverflow.com/questions/25718614/hours-elapsed-between-two-times-irrespective-of-country-and-time-zones) — Basil Bourque, Dec 25 '14 at 09:45

macrae2100 · Answer 1 · 2014-12-21T16:32:16.347

0

How about this?

DateTime t1, t2, t3,  reserve;

t1 = DateTime.Parse(inBox.Text); //from text box1 eg.11:30
t2 = DateTime.Parse(outBox.Text); //from text box2 eg.12:30
t3 = DateTime.Parse(breakBox.Text); //from text box3 eg.0:30

TimeSpan diffTime1 = t1 - t2;
TimeSpan diffTime2 = t2 - t3;

TimeSpan totalSpan = diffTime1 + diffTime2;

answerLabel.Text = diffTime2.ToString();

edited Dec 21 '14 at 16:32

answered Dec 21 '14 at 16:17

macrae2100

62
7

This won't work because the break must be a `TimeSpan` and not a `DateTime` and the break cannot be added it must be subtracted. – t3chb0t Dec 21 '14 at 17:49

t3chb0t · Accepted Answer · 2014-12-21T18:02:52.607

0

Based on the screenshot you provided in the link I think you are looking for this:

DateTime entryTime = DateTime.Parse("11:30");
DateTime exitTime = DateTime.Parse("14:30");
TimeSpan breakSpan = TimeSpan.Parse("0:30");
TimeSpan workSpan = (exitTime - entryTime - breakSpan);
answerLabel.Text = workSpan.ToString();

The break must not be a DateTime but a TimeSpan.

edited Dec 21 '14 at 18:02

answered Dec 21 '14 at 17:37

t3chb0t

16,340
13
78
118

You may accept this as an answer ;-) – t3chb0t Dec 22 '14 at 05:13
I edited your question. When you ask next time take it as an example ;-) – t3chb0t Dec 22 '14 at 06:59

How do I calculate the difference of times from three text boxes?

2 Answers2