VB DateDiff in C#

Question

User320184449 posted

Anyone know the best way to convert this to C# from VB, "Dim MinutesPast As Integer = DateDiff("n", dr("DateTime"), Now)"? I tried a couple code converters but they're not giving me anything that works. Thanks!

Answer 1

User475983607 posted

Anyone know the best way to convert this to C# from VB, "Dim MinutesPast As Integer = DateDiff("n", dr("DateTime"), Now)"? I tried a couple code converters but they're not giving me anything that works. Thanks!

DateTime Date1 = DateTime.Now.AddDays(-5);
TimeSpan diff = DateTime.Now - Date1;

Console.WriteLine(diff.TotalMinutes);

Works the same in VB.NET. 

Reference

https://docs.microsoft.com/en-us/dotnet/api/system.timespan?view=netcore-3.1

Answer 2

User320184449 posted

Yeah I seen that but I was hoping I could do it in a single line of code like I can do in VB. Having trouble getting that example implemented though, do I need to cast the SqlDataReader somehow? Trying this but it's not working:

DateTime date1 = dr["DateTime"];
TimeSpan diff = DateTime.Now - date1;

Answer 3

User409696431 posted

What are the variables you are passing to DateDiff?  What is "n", and what is "dr(DateTime)"?

In C# you would use TimeSpan

Are you looking for the number of days between two dates?

DateTime date1 = new DateTime(2020, 1, 1);
DateTime date2 = DateTime.Today;
int daysDiff = ((TimeSpan)(date2 - date1)).Days;

Minutes between two times? (This ignores date part, just looks at time.)

DateTime date1 = new DateTime(2020, 1, 1);
DateTime date2b = DateTime.Now;
int daysDiffmin = ((TimeSpan)(date2b - date1)).Minutes;

Total minutes between two dates? (Can't be int because it includes fractional minutes introduced by the seconds part of the datetime.)

double daysDifftotmin = ((TimeSpan)(date2b - date1)).TotalMinutes;

If you want the total minutes between two dates in int, you can add the first two results together.

...And so on. TimeSpan has lots of options. See: https://docs.microsoft.com/en-us/dotnet/api/system.timespan?view=netframework-4.8

Answer 4

User320184449 posted

The "n" is a minute format:
https://www.w3schools.com/asp/func_datediff.asp

Do you know how to cast an SqlDataReader into the DateTime in C#?

Answer 5

User320184449 posted

Oh wait, VisualStudio shows the fix: "DateTime date1 = (DateTime)dr["DateTime"];" Look at me, I'm learning C#..

Answer 6

User409696431 posted

Visual Studio gives excellent hints.  You do have to be in the ballpark of the right code.

Answer 7

User-821857111 posted

You always have to cast the DataReader to the correct type before you attempt any type-specific operation on it. The indexer returns an object type. 

Answer 8

User320184449 posted

Thank you both for making me smarter!