I want to calculate the time span between 2 times which I saved in a database.
So literally I want to know the length of time between the 2 values.
14:10:20 - 10:05:15 = 02:05:05
So the result would be 02:05:05.
How would I be able to achieve this using C#?
14:10:20 is the format I saved it in in my database.
Read the two time values into TimeSpan variables, then perform a .Subtract() on the bigger TimeSpan variable to get the TimeSpan result.
E.g. TimeSpan difference = t1.Subtract(t2);.
Your first step will be to get the timevalues stored in your database into .NET DateTime structs.
If you stored them as SQL-DateTime values in the database you can get them directly as DateTime. It would look something like this:
SQLCommand getTimeCommand = new SQLCommand("SELECT time FROM table", dbConnection);
SQLDataReader myReader = getTimeCommand.ExecuteReader();
while (myReader.Read())
{
DateTime time = myReader.GetDateTime(0);
}
myReader.Close();
Your implementation might differ, refer to the ADO.NET documentation in the MSDN library.
If you already got a string representing the time you can parse the string into a DateTime using the static methods
DateTime.Parse
or
DateTime.ParseExact
In your case you might need to use ParseExact, which can pe provided with a format-string defining how to read the string. Examples should be found in the MSDN library.
Durations in .NET are stored inside a TimeSpan struct. Getting the elapsed time between to datetimes is easy:
DateTime time1, time2; //filled with your timevalues from the db
TimeSpan elapsed = d2 - d1;
elapsed now contains the timespan between the two DateTimes. There are several members for the struct to access the TimeSpan. Look into the MSDN-Library to find the ones you need.
DateTime objects support the "-" operator so you can just read your times into such objects and subtract them. To test, check this out:
DateTime then = DateTime.Now;
Thread.Sleep(500);
DateTime now = DateTime.Now;
TimeSpan time = now - then;
MessageBox.Show(time.ToString());
Related
I have 1 single text box which a user will enter the number of hours. At present, if they enter 26 hours, we get an error because of the TimeSpan's HH limit. This value is going to get stored in a SQL Server 2008 Time(7) field.
How can I get it to recognize more than 23 hours? It is not an option to store it as a decimal because another section of the program requires this field to be a time(7) field.
TimeSpan estiamtedHours;
private void btnSave_Click(object sender, EventArgs e)
{
estimatedHours = TimeSpan.Parse(tbEstHours.Text);
}
The time(7) field also has the limit of 24 hours, what would be the best way round this as Time(7) is required for a Stopwatch on another form.
Thanks
If you know the input value is an hour value as a floating point number, you can use TimeSpan.FromHours():
TimeSpan estiamtedHours;
private void btnSave_Click(object sender, EventArgs e)
{
estimatedHours = TimeSpan.FromHours(Double.Parse(tbEstHours.Text));
}
Parse the text into an int and pass that int as the hours parameter in the TimeSpan constructor.
int hours;
if (Int32.TryParse(tbEstHours.Text, out hours))
{
TimeSpan ts = new TimeSpan(hours, 0, 0);
}
You can also do the same with minutes and seconds. Alternatively, if you just want hours, you can use TimeSpan.FromHours in the same manner instead of the TimeSpan constructor.
Be careful. TimeSpan is meant to measure an elapsed duration of time, while time in SQL Server is specifically a time-of-day. These are two different concepts.
Sometimes these get mixed up. For example, DateTime.TimeOfDay is a TimeSpan type - which goes against its design. It's a reasonable compromise since there is no Time type in .Net and it can fit.
But a TimeSpan that is 24 hours or greater will not fit into a SQL Server time field.
Also, a TimeSpan is based on standard days. You can create one with TimeSpan.FromHours(26) and it will represent "1 day and 2 hours". If you call TimeSpan.FromHours(26).ToString() it will be "1.02:00:00".
If you're storing an elapsed duration of time (not a time of day), then use a TimeSpan in .Net, but use an integer type in SQL Server. Decide what units you want precision for, and that will help you choose a data type.
For example, you can store the full precision of TimeSpan.Ticks using a SQL Server bigint type. But probably you will store TimeSpan.TotalSeconds using an int. When loading, you can use TimeSpan.FromSeconds to get back to a TimeSpan type.
Also be aware that a TimeSpan can be negative, which represents moving backwards in time.
By the way, if you used the Noda Time library - these concepts would be separated for you in types called Duration and LocalTime.
If what you were after is a way to parse a string like "26:00:00" you can't do that with a TimeSpan. But you can use Noda Time:
// starting from this string
string s = "26:00:00";
// Parse as a Duration using the Noda Time Pattern API
DurationPattern pattern = DurationPattern.CreateWithInvariantCulture("H:mm:ss");
Duration d = pattern.Parse(s).Value;
Debug.WriteLine(pattern.Format(d)); // 26:00:00
// if you want a TimeSpan, you can still get one.
TimeSpan ts = d.ToTimeSpan();
Debug.WriteLine(ts); // 1.02:00:00
After parsing the input, use the FromHours method:
double hours
if (double.TryParse(tbEstHours.Text, out hours)
{
TimeSpan time = TimeSpan.FromHours(hours);
}
The TimeSpan.Parse Method expects the input in the format
[ws][-]{ d | [d.]hh:mm[:ss[.ff]] }[ws]
where hh is the hour part, ranging from 0 to 23.
For example,
TimeSpan.Parse("5") returns 5 days,
TimeSpan.Parse("5:14") returns 5 hours and 14 minutes.
If you just want your users to enter a number of hours, you can simply parse the input as an integer and construct a TimeSpan from that:
TimeSpan result = TimeSpan.FromHours(int.Parse("26"));
// result == {1.02:00:00}
(Use int.TryParse for user input.)
If you want your users to enter both hours and minutes (such as 26:14), then you need to implement some parsing method yourself.
Since the other answers don't address this
The concern here is the time column in the database and it expects a valid duration which would be limited to the 24 hr time where as TimeSpan can have them beyond the 24 hr limit.
So you should ideally parse the value as int (use int.Parse or int.TryParse) and then check if it is less than 24 and then create the appropriate TimeSpan
In PHP, you can write the following:
date_default_timezone_set("UTC");
How do I do I write this in C#?
Also, how do I write this:
declare(ticks=1);
in C#?
In c#, the timezone is built into the DateTime structure, so you should not need to set the default. Instead when you are manipulating DateTime instances you use the UTC version of methods. For example, in the constructor you can specify if the date supplied is local or UTC.
With regards to the second question, are you just wanting the syntax of
int ticks = 1; // or
var ticks = 1;
If you are trying to add a time period to a date, you should use a TimeSpan, along the lines of:
TimeSpan ticks = new TimeSpan(1);
Using Visual Studio 2008 (C#) I have to make a working clock (digital) with the current time zone hour, and a few more with different time zones, like new york, etc.
inside the form I put 2 labels (for the clocks) and a timer, inside the timer I put this code:
timer1.Interval = 1000;
label1.Text = DateTime.Now.ToLongTimeString();
DateTime myDateTime = DateTime.Now;
TimeSpan myTimeSpan = new TimeSpan(2, 0, 0);
DateTime myDateTime8 = myDateTime + myTimeSpan;
label2.Text = ("" + myDateTime8);
the part with the timespan does add 2 hours to the clock, however, instead of just the actually clock I also get the date on it's left, like for example:
"17-05-2011 22:38:00"
I need to know how can I add/subtract hours and only show the clock.
Instead of adding a timespan, simply call the AddHours method:
myDateTime.AddHours(2).ToLongTimeString();
myDateTime.ToShortTimeString() will return you only time
or as Tejs mentioned you can use ToLongTimeString() that I guess more suits your requirement.
For adding or subtracting hours you can use dateTime.AddHours(even hours in negative) or for subtracting you can also use dateTime.Subtract(time to subtract)
Using the .ToString() method of the timespan method allows you to output the date in any format you want. See http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx
For your time zone needs, use an approach similar to the one suggested in this MSDN article. Notably:
Use ConvertTimeToUtc to get UTC time before performing any arithmetics.
Perform required arithmetics.
Convert back to local time using TimeZoneInfo.ConvertTime.
To get just the time part of a DateTime, use DateTime.ToShortTimeString(). Note that this is culture-aware, so if you want a fixed format, consider using DateTime.ToString() to specify a format.
can someone tell me how to conver DatePicker value to DateTime value...
I have this variables:
DateTime now = DateTime.Now;
DatePicker rd = rd_datePicker;
I would like to get difference in days betwen this two dates, can you help me with this too?
Have you tried using DatePicker.SelectedDate?
Once you've got the two DateTime values (you may want to use DateTime.Today instead of DateTime.Now) you can subtract one from the other to get a TimeSpan, and then use TimeSpan.TotalDays to find out the number of days in the period.
(As DateTime is effectively a "local" representation, you don't need to worry about time zones or variable day lengths in this particular case. Date and time arithmetic in general is rather tricky...)
DatePicker dp = new DatePicker();
DateTime dt=new DateTime();
dp.Text = dt.Date.ToString("yyyy/MM/dd");
I am developing a c#.net app in which I need to subtract two time periods.
I have taken two date objects and subtracted them but it doesn't work.
TimeSpan can be used to measure the differences between 2 DateTimes:
DateTime dt1 = ...
DateTime dt2 = ...
TimeSpan diff = dt2 - dt1;
Check the TimeSpan struct.
Also, for DateTime, you have handy procedures such as AddDays:
DateTime later = mydate.AddDays(1.0);
Similarlly, there are AddHours, AddMonths and even AddMilliseconds:
http://msdn.microsoft.com/en-us/library/system.datetime_members.aspx
Subtracting one DateTime from another returns a Timespan object. which basically tells you how many days/hours/mins/secs/milliseconds/ticks that occured between the 2 DateTimes.