C# - calculate number of hours away from a deadline

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Hi,

I have attempted this question and I need a tiny bit of help with the last part. I'm constantly doing research, as I'm new to this, but help from people is beneficial.
Please see what I have done so far below.

The problem is, it is saying that "the call is ambiguous between the following methods or properties: 'Math.Round(double, int)' and 'Math.Round(decimal, int)'.

As far as I am aware, I need to convert the variable into a decimal or a double, and then round this to 2dp, but I am having issues doing this successfully (i.e. I know what I want to do, but as far as coding it correctly without errors, I have not been able to do that as of yet).

Regards.

What I have tried:

public static double HowManyHoursFromNow(DateTime deadline)
{
    var remaining = deadline.Subtract(DateTime.Now).Hours;

    return Math.Round(remaining, 2);
}

Posted 13-Jul-17 0:30am

Member 13302374

Updated 13-Jul-17 0:46am

TheRealSteveJudge

v2

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3 solutions

Solution 2

The DateTime.Subtract method returns a TimeSpan object, and the Hours property of that is an int. So Math.Round cannot do anything with it as it has no fractional part; you can only round a Decimal or Double type as described in Math.Round Method (System)[^].

Posted 13-Jul-17 0:42am

Richard MacCutchan

Solution 3

You should use the TotalHours property which represents whole and fractional hours.

public static double HowManyHoursFromNow(DateTime deadline)
{
    var remaining = deadline.Subtract(DateTime.Now).TotalHours;

    return Math.Round(remaining, MidpointRounding.AwayFromZero);
}

Posted 13-Jul-17 0:46am

TheRealSteveJudge

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Andy Lanng · Accepted Answer · 2017-07-13T00:36:00

Solution 1

Timespan has several properties. You can get the Days/Hours and Minutes components but:

The Hours will never go over 23. this is handled in the Days property. It will never be more precise than and int. this is handled by the Minute property
The minutes will never go over 59. etc...

What you're looking for is the TotalHours. This can be over 23 and is as precise as a double can be.

Posted 13-Jul-17 0:36am

Andy Lanng

Comments

Member 13302374 13-Jul-17 6:39am

Thank you Sir!

Member 13302374 13-Jul-17 7:16am

So, let's say for example, I had a question like: Given the date and time of an appointment return how many days it is in the future (in full days e.g. at 11pm tonight, an appointment at 9am tomorrow is 1 day).

My code would be:
public static int HowManyDaysFromToday(DateTime appointment)
{return appointment.TimeOfDay.Subtract(DateTime.Now.TimeOfDay).TotalDays;}

Is this correct?

Andy Lanng 13-Jul-17 7:28am

No. The issue here is that a timespan has no reference to when it starts or finishes. between 11pm and 9am there are 10 hours. 10 hours is the only detail stored in a timespan. It's the exact same object as 11am to 9pm the same day

You would need to compare the dates as a part of the equation. For I full answer I'll need you to post a new question :S

Member 13302374 13-Jul-17 7:33am

I've posted a new question :)

Andy Lanng 13-Jul-17 7:52am

Oh, I don't see it ?
Can you post the link plz ^_^

Member 13302374 13-Jul-17 8:32am

They closed the post because it was not clear enough. Let me try and update it now, although it's the same as the one above

Member 13302374 13-Jul-17 8:41am

https://www.codeproject.com/Questions/1196326/Csharp-calculate-number-of-days-away-from-a-deadli

Member 13302374 13-Jul-17 8:41am

That my updated question, Andy. Thanks