Date/Time calcuations not working

John Riker

5y769Learn iOS Programming

Not sure if it's because it hit a day but I have a calculation:

((DateTime.Now - lastdownloaded).Hours > 4)

It's returning 0

Used to work. The values right now are

Now: 11/18/2020 4:51:50 PM

lastdownloaded 11/17/2020 4:40:38 PM

It comes out to: 1.00:12:18.1796374

Shouldn't this be 24 hours or something? Sounds like it's literally taking the hours value on the subtraction and not the total hours between the two values. Any clarity on what this is doing? Also how do I get it to return what I'm looking for in other words the total hours between the two date/times?

Thanks.

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
@Nitin Sontakke sir,
Thanks for pointing out the mistake , its appreciating , for total hours in between
difference.TotalHours
is there.
difference.Hours
will just give the Hour component.
Nitin Sontakke5y ago
Just had a closer look at the code by Sachin and Kiran.

The correct property to be used is TotalHours and not Hours.

https://docs.microsoft.com/en-us/dotnet/api/system.timespan?view=net-5.0
Nitin Sontakke5y ago
It is indeed a bad approach.

.NET has given a dedicated data type (structure) to store the absolute difference between two datatime strcutures, namely timespan as correctly shown by other experts.

Please use timespan.

I am not too sure, if you will be convinced by this, but consider a junior developer reading your code years later.
John Riker5y ago
Thanks for the input. I ended up going with:

(((DateTime.Now - lastdownloaded).Days * 24) + (DateTime.Now - lastdownloaded).Hours)

Not sure if that's a bad approach or not.

Thanks.

JR
Mageshwaran R5y ago
Hi John,
please refer this link,
https://www.c-sharpcorner.com/article/calculating-date-difference-in-C-Sharp/
Kiran Mohanty5y ago
Hi ,
Here is the code that may help you.
           CultureInfo cultures = new CultureInfo("en-US");
           DateTime d1 = Convert.ToDateTime("11/18/2020 4:51:50 PM", cultures);
           DateTime d2 = Convert.ToDateTime("11/17/2020 4:40:50 PM", cultures);
           TimeSpan t = d1-d2;
           var totalHours = (t.Days*24)+ t.Hours;
           Console.WriteLine(totalHours);
Sachin Singh5y ago
difference of dateTime in c# will give you datetime result not integer result , what you need is Timespan.
TimeSpan difference = DateTime.Now - lastDownloaded;
int days = difference.Days;
int hours = difference.Hours;
int minutes = difference.Minutes;