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Found what I needed right after I posted (of course). Thank you for the help. I wasn't understanding TimeSpan and didn't realize I could simply tack .TotalHours to the end of my TimeSpan variable to get what I needed.

Please explain like I'm 5 years old.

I have two DateTimePicker objects with a custom format of HH:mm so that only military time is entered. Date is irrelevant. One picker is for the start time and the other picker is for the end time.

I need to be able to subtract the start time from the end time in order to get a total length of time in hours between them.

I then need this length of time converted to an integer I suppose? So that I can later use an if statement to see if it is equal to or above a certain number.

I know that DateTime can use the > < and other operators, so that's what I'd like to use.

However when I try to create a variable like so:

var timeLength = endTime.Value - startTime.Value;

It tells me its a TimeSpan variable.

I tried to make a DateTime variable so I could use the > < and other operators later:

DateTime timeLength = endTime.Value - startTime.Value;

And I get red squigglies

"Cannot implicitly convert type 'System.TimeSpan' to 'System.DateTime'

Well okay VS, I don't want a TimeSpan variable. At least I don't think I do?

Anyway, obviously this means I can't later user the shiftLength variable to compare to things, so that's not working.

I tried to do it straight in my if statement:

if (endTime.Value - startTime.Value <= 12)

Operator '<=' cannot be applied to operands of type 'TimeSpan' and 'int'

Alright. Fine. So.

1) Why is it calling this a TimeSpan variable. I'm trying to look into TimeSpan properties and it's confusing the heck out of me. Do I need to use TimeSpan to accomplish what I'm trying to do? and if not..

2) What's the simplest way to subtract my DateTimePicker endTime.Value from my startTime.Value to be able to compare it to an integer with < > = operators?

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irisshootsface
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  • Why don't you want a TimeSpan? Did you take a look at the properties it offers you? I recommend reading the [docs](https://learn.microsoft.com/en-us/dotnet/api/system.timespan?view=netframework-4.7.2). – ProgrammingLlama Dec 07 '18 at 01:21
  • I didn't know if I had to. I dug a bit deeper just a moment after I posted this and found what I was looking for (the .TotalHours thing I think). I'm still having trouble understanding the documentation on everything to be honest.. the way its worded confuses me. – irisshootsface Dec 07 '18 at 01:25
  • The MS Docs have never been particularly clear! The last attempt they've made seems worse than previous TBH – Mitch Wheat Dec 07 '18 at 01:29
  • At least I'm not the only one.. I felt kinda dumb for not being able to understand it lol – irisshootsface Dec 07 '18 at 01:32
  • A `DateTime` represents a point in time. A `TimeSpan` represents the passage of time (whether a few milliseconds or 2 centuries). If you subtract 2 DateTimes, you get a TimeSpan that represents the amount of time that passed between those 2 points in time. If you add a TimeSpan to a DateTime, you get a new DateTime offset by the span. Both have useful properties and methods. If you want to represent 6pm tonight, you can say `DateTime.Now.Day` to get midnight this morning & then add `TimeSpan.FromHours(18)` to get to 6pm. – Flydog57 Dec 07 '18 at 02:14

1 Answers1

3

Use the TotalMinutes (TotalHours, TotalSeconds etc) property of the TimeSpan:

if ((endTime.Value - startTime.Value).TotalHours <= 12)
{
    ....
}

Ref.: TimeSpan

Mitch Wheat
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