I'm trying to get the number of days (calculated byu datediff) in sql and the number of days in c# (calculated by DateTime.now.Substract) to be the same, but they return different results....
//returns 0
int reso = DateTime.Now.Subtract(expirationDate).Days;
vs
//returns 1
dateDiff(dd,getDate(),ExpirationDate)
In both cases, ExpirationDate is '10/1/2011 00:00:00', and the code and the DB are sitting on the same server. I want the return int to be the same. I suspect I'm missing something stupid... ideas??
dateDiff(dd,getDate(),ExpirationDate) Is doing a days comparison. DateTime.Now.Subtract(expirationDate).Days is doing a date and time
For example
SELECT dateDiff(dd,'10/1/2011 23:59:00' , '10/2/2011') returns one day even when only one minute apart.
If you want the same in C# you need to remove the time component
e.g.
DateTime dt1 = new DateTime(2011,10,1, 23,59,0);
DateTime dt2 = new DateTime(2011,10,2, 0,0,0);
Console.WriteLine((int) dt2.Subtract(dt1.Subtract(dt1.TimeOfDay)));
So in your case it would be something like
DateTime CurrentDate = DateTime.Now;
int reso = CurrentDate.Subtract(CurrentDate.TimeOfDay).Subtract(DateTime.expirationDate).Days;
I haven't tested it but I would not do
DateTime.Now.Subtract(DateTime.Now.Subtract.TimeOfDay)
Because the second call to Now wouldn't be guaranteeing to be the same as first call to Now
In any case Stealth Rabbi's answer seems more elegant anyway since you're looking for a TimeSpan not a DateTime
10/1/2011 is less than 1 day away from DateTime.Now. Since you're getting back a TimeSpan and then applying Days to it, you're getting back a TimeSpan that is < 1 day. So it'll return 0 Days.
Instead, just use the Date component of those DateTimes and it'll correctly report the number of days apart - like this:
DateTime now = DateTime.Now;
DateTime tomorrow = new DateTime(2011, 10, 1);
var val = (tomorrow.Date - now.Date).Days;
This will yield you 1 day.
I'm assuming you want the number of Total days, not the number of days from the largest previous unit. You'd want to use the TotalDays property. Also, you may find it easier to use the minus operator to do a subtraction
DateTime d1 = DateTime.Now;
DateTime d2 = new DateTime(2009, 1, 2);
TimeSpan difference = d1 - d2;
Console.WriteLine(difference.TotalDays); // Outputs (today):1001.46817997424
Related
I wanted to find if two DateTime are within a week.
One of them is the current system Datetime, which I got it by using:
DateTime CurrentDateTime = new DateTime();
CurrentDateTime = DateTime.Now;
The other DateTime will just be a selected date. Assuming it is stored in a variable called : ExportDate.
So, I can find the difference between them by doing
ExportDate.Subtract(CurrentDateTime)
But I cannot change this value into a int for comparing...
So how should I compare this to DateTime to see if this two dates are greater then 0Days, and less then 7Days.
Subtracting two datetimes gives you a TimeSpan. This class comes with a property called TotalDays.
Gets the value of the current TimeSpan structure expressed in whole and fractional days.
Src: https://msdn.microsoft.com/en-Us/library/system.timespan(v=vs.110).aspx
You can use to count the number of days I guess.
Regards,
Seb
Try to compare the TotalDays of the resulting TimeSpan. Depending on which is later, the result must be between -7 and 7. Use Math.Abs to avoid comparing the value against both bounds:
bool isWithinWeek = Math.Abs(ExportDate - CurrentDate).TotalDays) < 7
If the time of day is irrelevant, compare only the dates:
bool isWithinWeek = Math.Abs(ExportDate.Date - CurrentDate.Date).TotalDays) < 7
You can use
(ExportDate - CurrentDateTime).TotalDays <= 7
You can simply use the DayOfYear property of DateTime to get the day in the year and then check if the difference is less than 7 or not. You can try:
bool isWithinAWeek = Math.Abs(currentDateTime.DayOfYear-exportDate.DayOfYear)>7?false:true;
What is the best way to compare two DateTime in a specific format and trigger code if DateTime has passed.
My DateTime is formatted as 4/26/2017 10:00:00 AM
DateTime currentDateTime = DateTime.Now;
DateTime eventDateTime = DateTime.Parse("4/26/2017 10:00:00 AM");
int result = DateTime.Compare(currentDateTime, eventDateTime);
if (result < 0)
Response.Write( "is earlier than Do Nothing");
else if (result == 0)
Response.Write("is the same time as: Do Nothing");
else
Response.Write("Time is greater, Trigger Action ");
Is the above code fine for comparison or we can improve it.
For my opinion, the method you suggested is the most efficiant and accepted way to compare 2 DateTime variables in C#, considering you need to take action if the 2 dates are also equal.
Side note:
If you only needed to compare the 2 DateTime without the equal condition, you could just write:
if (currentDateTime < eventDateTime)
Response.Write("is earlier than Do Nothing");
else
Response.Write("Time is greater, Trigger Action");
which is a bit cleaner and more efficiant.
To compare Dates, your method is efficient one because according to MSDN
The CompareTo method compares the Ticks property of the current instance and value but ignores their Kind property. Before comparing DateTime objects, make sure that the objects represent times in the same time zone.
So as it does compare Ticks of two instances of DateTime, so it is the efficient method for comparison.
As a side note, if you want to find interval between DateTime Instances then you can use DateTime.Subtraction it will give TimeSpan of both DateTime instances. So you can find total difference in their minutes, hours, days, seconds, milliseconds by using TimeSpan properties.
DateTime date1 = new DateTime(2010, 1, 1, 8, 0, 15);
DateTime dateNow = DateTime.Now;
TimeSpan interval = dateNow.Subtract(date1);
double totalHours= interval.TotalHours;
double totalMinutes = interval.TotalMinutes;
double totalSeconds= interval.TotalSeconds;
double totalMilliseconds= interval.TotalMilliseconds;
You can use nested if else statement as below:
if (currentDateTime < eventDateTime)
Response.Write("is earlier than Do Nothing");
else if(currentDateTime > eventDateTime)
Response.Write("time is greater, Trigger Action");
else
Response.Write("is the same time as: Do Nothing");
I want to convert a Timespan to Datetime. How can I do this?
I found one method on Google:
DateTime dt;
TimeSpan ts="XXX";
//We can covnert 'ts' to 'dt' like this:
dt= Convert.ToDateTime(ts.ToString());
Is there any other way to do this?
It is not very logical to convert TimeSpan to DateTime. Try to understand what leppie said above. TimeSpan is a duration say 6 Days 5 Hours 40 minutes. It is not a Date. If I say 6 Days; Can you deduce a Date from it? The answer is NO unless you have a REFERENCE Date.
So if you want to convert TimeSpan to DateTime you need a reference date. 6 Days & 5 Hours from when? So you can write something like this:
DateTime dt = new DateTime(2012, 01, 01);
TimeSpan ts = new TimeSpan(1, 0, 0, 0, 0);
dt = dt + ts;
While the selected answer is strictly correct, I believe I understand what the OP is trying to get at here as I had a similar issue.
I had a TimeSpan which I wished to display in a grid control (as just hh:mm) but the grid didn't appear to understand TimeSpan, only DateTime . The OP has a similar scenario where only the TimeSpan is the relevant part but didn't consider the necessity of adding the DateTime reference point.
So, as indicated above, I simply added DateTime.MinValue (though any date will do) which is subsequently ignored by the grid when it renders the timespan as a time portion of the resulting date.
TimeSpan can be added to a fresh DateTime to achieve this.
TimeSpan ts="XXX";
DateTime dt = new DateTime() + ts;
But as mentioned before, it is not strictly logical without a valid start date. I have encountered
a use-case where i required only the time aspect. will work fine as long as the logic is correct.
You need a reference date for this to be useful.
An example from
http://msdn.microsoft.com/en-us/library/system.datetime.add.aspx
// Calculate what day of the week is 36 days from this instant.
System.DateTime today = System.DateTime.Now;
System.TimeSpan duration = new System.TimeSpan(36, 0, 0, 0);
System.DateTime answer = today.Add(duration);
System.Console.WriteLine("{0:dddd}", answer);
Worked for me.
var StartTime = new DateTime(item.StartTime.Ticks);
If you only need to show time value in a datagrid or label similar, best way is convert directly time in datetime datatype.
SELECT CONVERT(datetime,myTimeField) as myTimeField FROM Table1
You could also use DateTime.FromFileTime(finishTime) where finishTme is a long containing the ticks of a time. Or FromFileTimeUtc.
An easy method, use ticks:
new DateTime((DateTime.Now - DateTime.Now.AddHours(-1.55)).Ticks).ToString("HH:mm:ss:fff")
This function will give you a date (Without Day / Month / Year)
A problem with all of the above is that the conversion returns the incorrect number of days as specified in the TimeSpan.
Using the above, the below returns 3 and not 2.
Ideas on how to preserve the 2 days in the TimeSpan arguments and return them as the DateTime day?
public void should_return_totaldays()
{
_ts = new TimeSpan(2, 1, 30, 10);
var format = "dd";
var returnedVal = _ts.ToString(format);
Assert.That(returnedVal, Is.EqualTo("2")); //returns 3 not 2
}
First, convert the timespan to a string, then to DateTime, then back to a string:
Convert.ToDateTime(timespan.SelectedTime.ToString()).ToShortTimeString();
I am comparing the time now to a time stored somewhere in a database. The time stored in the database is in the format of "yyyyMMddHHmmss". For example, the database may return 201106203354 for a stored time value. I am then using a function to compare the time now to the time read in from the database.
What I am doing now:
Create 6 int variables
Take the sub-string from the formatted date string and convert the sub-string to an int32.
Pass the 6 int variables to the function.
What I would like to do:
Rather than splitting up the formatted date-time string, and seperately creating and assigning six variables to pass to the function, I would like to know if there is some way to simply convert the formatted date-time string into DateTime.
Please see my code as it will help to explain what I clearly cannot ...
Pass time now along with time read from database:
Private void passTime()
{
string timeStamp;
int year, month, day, hour, minutes, seconds;
DateTime dt = DateTime.Now;
timeStamp = dt.ToString("yyyyMMddHHmmss");
year = Convert.ToInt32(timeStamp.Substring(0, 4));
month = Convert.ToInt32(timeStamp.Substring(4, 2));
day = Convert.ToInt32(timeStamp.Substring(6, 2));
hour = Convert.ToInt32(timeStamp.Substring(8, 2));
minutes = Convert.ToInt32(timeStamp.Substring(10, 2));
seconds = Convert.ToInt32(timeStamp.Substring(12, 2));
MessageBox.Show(GetDifferenceDate(
new DateTime(year,month,day,hour,minutes,seconds),
// Example time from database
new DateTime(2011, 08, 11, 11, 40, 26)));
}
static string GetDifferenceDate(DateTime date1, DateTime date2)
{
if (DateTime.Compare(date1, date2) >= 0)
{
TimeSpan ts = date1.Subtract(date2);
return string.Format("{0} days",
ts.Days);
}
else
return "Not valid";
}
So, quite simply, I would like to compare two dates that are both in the format of "yyyyMMddHHmmss", or if this is not possible, I would like to convert the previous Date string into a DateTime.
I'm sure I left something out here, I will go back and read it again but please feel free to ask me anything that I left unclear.
Thank you,
Evan
You're looking for ParseExact:
DateTime.ParseExact(timeStamp, "yyyyMMddHHmmss", CultureInfo.InvariantCulture)
I have two dates as duedate as 03/03/2011 and returndate as 03/09/2011. I want to find the fine in double when I subtract duedate from returndate.How can duedate be incremented?
Following code might help you:
var dueDate = new DateTime(2011, 3, 3);
//if you want to increment six days
var dueDatePlus6Days = dueDate.AddDays(6);
//if you want to increment six months
var dueDatePlus6Months = dueDate.AddMonths(6);
var daysDiff1 = (dueDatePlus6Days - dueDate).TotalDays; //gives 6
var daysDiff2 = (dueDatePlus6Months - dueDate).TotalDays; //gives 184
The logical solution would seem to be the AddDays method, as in the other answers.
However, I try (in general) never to use floating point (i.e. a double) when working with monetary or date values.
DateTime contains a time component and AddDays takes a double as argument (fractional part becomes time), so I tend to avoid use of that method.
Instead, I use
dueDatePlusOne = dueDate.AddTicks(TimeSpan.TicksPerDay);
This should result in slightly faster execution too. Not that it still matters much on today's hardware, but I started out coding for microprocessors with a <1 MHz clock speed and old PDP-8's and -11's and stuff like that back in the 1970's, and some habits never die ;)
Assuming returnDate, dueDate are DateTime objects:
double extraDays = (returnDate - dueDate).TotalDays;
May this can help you
DateTime dt_duedate = DateTime.Now;
DateTime dt_returndate = DateTime.Now.AddDays(2);
System.TimeSpan diffResult = dt_returndate.Subtract(dt_duedate);