Develop Reference

Time-dependent coloring in C#

I need time-dependent coloring in a project. If the system is 10 minutes past the entrance time, the background will be orange. If it is 20 minutes past it will be red. I found the difference between the two dates using the
DateTime.Parse(timeNow).Subtract(DateTime.Parse(timeLogged));
but I can't compare the result.
if(Convert.ToInt32(DateTime.Parse(timeNow).Subtract(DateTime.Parse(timeLogged)))>10)
Does it have a similar use? Can you help me how to do it?
I am using Google Translate because my English is not very good, and I apologize for the language mistakes I made.

You can subtract DateTime objects. You'll get a TimeSpan. You can use that TimeSpan to determine the difference between the original objects:
DateTime now = DateTime.Parse(timeNow);
DateTime logged = DateTime.Parse(timeLogged);
TimeSpan diff = now - logged;
if (diff.TotalMinutes > 10)
// It's been more than 10 minutes.

You could do this aswell
// If older than 20 min
if(DateTime.Parse(timeLogged) < DateTime.Now.AddMinutes(-20))
{
// Do stuff
}

DateTime.Subtract returns a Timespan object that has a TotalMinutes property, so you could do this:
if (DateTime.Parse(timeNow).Subtract(DateTime.Parse(timeLogged)).TotalMinutes > 10)

How can i convert time to minutes using Sql queries e.g "02:30:05' to 150.5 minutes

I am working on a billing system and its based on time-in and time-out. Rate is R5 per 30 minutes charged to users for loaning an item.
I managed to get the Time difference and got time as "02:30:05" now how can i convert this time to minutes and have "02:30:00" = "150 min" so that I can be able to divide time by 30 minutes, to be able to multiply by the rate to generate my bill. as I can not divide Date time with a number. I want something like (150 min/30 min = 5 ans) , (5 ans * 5 rate = R25 bill) I hope its clear guys i'm a beginner so please do say if I'm not making any sense. thank you in advance for your help.

try this one. it will calculate total minutes
SELECT LTRIM(DATEDIFF(MINUTE, 0, TimeSpent))
FROM yourtable
TimeSpent will be your datetime variable

I believe that you are getting time difference in TimeSpan. Then you can use to get total minutes:
timeSpan.TotalMinutes;
If you have the result in string then you must tryparse to get timespan:
string time = "02:30:00";
TimeSpan timeSpan;
if (TimeSpan.TryParse(time, out timeSpan))
{
var aa = timeSpan.TotalMinutes;
}

Since you didn't mention what is your dbms I'll provide you with the syntax of SqlServer that gives the difference of 2 times on minutes:
SELECT DateDiff(mi, #timeIN, #TimeOut)
The first parameter allows you to choose in what datepart you need the difference.
For years write YY
For months write MM
For days write DD
For hours write hh
For minutes write mi
For seconds write ss

convert min, sec to a 0.xxx notation in c#

I am new to c#. For school I have to make an exercise that converts the hours, minutes and seconds to a numeric value. So 37 min and 30sec becomes 0.625. Anyone know how to do this?
thanks a lot

var duration = new TimeSpan(0, 37, 30);
string s = duration.TotalHours.ToString("0.###");
// s === "0.625"

Assuming that you want hours, minutes and seconds to be converted to hours, you would do it like this:
double result = hours + minutes/60.0 + seconds/(60.0 * 60.0);
This is because a minute is 1/60th of an hour and a second is 1/3600th of an hour (3600 == 60 * 60) so the calculation uses simple scaling.
I'm thinking that you will need to show these kinds of calculations rather than using TimeSpan, if the teacher is looking to see if you understand the conversion logic.

Won't provide a copy/paste ready solution (homework :-p), but the TimeSpan class has everything you need: Parse methods and constructors to build a TimeSpan from various times (hours, minutes,...) and properties to return results as minutes, hours...

You will first want to convert the hours, minutes and seconds to a total number of seconds. Then you can compare that to the number of seconds in one hour. Take care when doing integer devision, you will first have to convert to a double!

Calculate time difference using TimeSpan

I am trying to calculate the time difference of two given times slots but the answers does not seem to be correct what am I doing wrong?
My code:
For some reason the value given amFinish is changed from 16:30 to 16:18:00 I have no idea why!
And What if I have a text box and the user enters 16.30 how would I take that value and compute it as 16hrs and 30mins
The answer should be 05.30 but instead I get 05.18. Any sugestions?

30% of an hour is 18 minutes.
16.30 hours is 16 hours and 30/100 parts of an hour.
16 hours and a half would be 16.50.

You have decimal 16.3 hours, which is 16 hours and 18 minutes as Oded explains.
If you need to specify both hours, minutes, and seconds, use the overload of the TimeSpan constructor which takes three arguments:
TimeSpan amStart = new TimeSpan(0, 11, 0);
TimeSpan amFinish = new TimeSpan(16, 30, 0);
And if you need to convert a string into a TimeSpan, use something like:
TimeSpan amFinish = TimeSpan.ParseExact("16.30", #"hh\.mm", CultureInfo.InvariantCulture);

Time difference between 2 timespans fails to return expected data

I have created 2 Timespans below:
TimeSpan currentTs = TimeSpan.FromSeconds(43995); //12:13:15
TimeSpan towTime = TimeSpan.FromSeconds(303072); //12:11:12
I'm trying to find the difference in minutes (by the seconds I'm passing it, it looks like they are on different days). I am hoping for around 2 minutes difference, but in reality, I'm getting -57 minutes.
int timeDifference = (int)currentTs.Subtract(towTime).Minutes;
Can someone explain what i am doing wrong?

If you are just looking for the difference between the minutes (not including the days, hours or seconds), then you can use
double timeDifference = currentTs.Minutes - towTime.Minutes; // 2
This is just the difference of the minutes component though. As other people have said, these times are separated by 3 days, so a TimeSpan possibly isn't ideal.
Or, If you want the seconds to be included as well, you can use
TimeSpan minutes1 = new TimeSpan (0, currentTs.Minutes, currentTs.Seconds);
TimeSpan minutes2 = new TimeSpan (0, towTime.Minutes, towTime.Seconds);
double timeDifference = minutes1.TotalMinutes - minutes2.TotalMinutes // 2.05;

You are looking for the TotalMinutes property not Minutes - the later is just the minutes part of the time difference, the former is the full time difference expressed in fractional minutes:
double timeDifference = currentTs.Subtract(towTime).TotalMinutes;
Also easier to read is:
double timeDifference = (currentTs - towTime).TotalMinutes;

I'm guessing you want to completely ignore the fact that the times are different by about 3 days. In that case, if you take the remainder after division by 86400 (the number of seconds in a day) and pass that to TimeSpan.FromSeconds, you should hopefully get what you want:
TimeSpan currentTs = TimeSpan.FromSeconds(43995 % 86400); //12:13:15
TimeSpan towTime = TimeSpan.FromSeconds(303072 % 86400); //12:11:12, ignoring the 3 days.
double timeDifference = (currentTs - towTime).TotalMinutes;
I got the value of timeDifference as 2.05 when I tried this.
Of course, if currentTs is earlier in the day than towTime (perhaps because midnight falls between them), the time difference will come out negative. If you still want to count the number of minutes between the two, assuming that currentTs is always after towTime, then you'll need to add 1440 (the number of minutes in a day) to timeDifference if it works out negative:
if (timeDifference < 0)
{
timeDifference += 1440;
}

Because the second timespan isn't 12:11:12, its 3:12:11:12.
So you're going to get a negative result which would be in the thousands if you did total minutes (since its representing something like -2days, 57 minutes, 57 seconds)...since you just ask for Minutes and not TotalMinutes you just get the -57.

currentTime is less then towTime (you seem to be missing one digit).