Convert System Date and time into integer - c#

Well I am trying to convert System's current date and time into integer value and then adding it into List.
The code is
List<int> _data = new List<int>();
foreach (DataRow row in dt.Rows)
{
_data.Add((int)Convert.ToInt32(DateTime.Now.ToLocalTime()));
_data.Add((int)Convert.ToInt32(row["S11"]));
}
JavaScriptSerializer jss = new JavaScriptSerializer();
chartData = jss.Serialize(_data);
Response.Write(chartData);
I am getting error which says Invalid cast from "DateTime' to 'Int32'
I want to convert in such form to make the json which look like[1386216561000,74] Here the first member is time in integer format and second is the data which is coming from sql server.
Actually what I am trying to do is something similar to this php code.
The code is
<?php
// Set the JSON header
header("Content-type: text/json");
$x = time() * 1000;
// The y value is a random number
$y = rand(0, 100);
// Create a PHP array and echo it as JSON
$ret = array($x, $y);
echo json_encode($ret);
?>


You need to convert your time to Epoch time or to some timespan value from a certain reference point.
Here is the code how you calculate a epoch time:
var timeDiff=DateTime.UtcNow - new DateTime(1970, 1, 1);
var totaltime = timeDiff.TotalMilliseconds;


The PHP time() function returns the current time measured in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT).
So to mimic this functionality in C#, try this:
private static double GetUnixEpoch(this DateTime dateTime)
{
var unixTime = dateTime.ToUniversalTime() -
new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return unixTime.TotalSeconds;
}
Usage:
var unixTime1 = DateTime.Now.GetUnixEpoch();
Note: GetUnixEpoch returns a double.
So your code should read like this:
List<double> _data = new List<double>();
foreach (DataRow row in dt.Rows)
{
_data.Add(DateTime.Now.GetUnixEpoch());
_data.Add((double)Convert.ToDouble(row["S11"]));
}
JavaScriptSerializer jss = new JavaScriptSerializer();
chartData = jss.Serialize(_data);
Response.Write(chartData);


DateTime cannot be implicitly converted to int. Consider using ToString() with format. For example...
_data.Add((int)Convert.ToInt32(DateTime.Now.ToLocalTime().ToString("HHmmssfff"));
Good Luck!


You can convert your date into UnixTime Stamp :
Convert Date Into UnixTimeStamp :
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
return (dateTime - new DateTime(1970, 1, 1).ToLocalTime()).TotalSeconds;
}
Converta UnitTimeStamp to Date :
public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
{
// Unix timestamp is seconds past epoch
System.DateTime dtDateTime = new DateTime(1970,1,1,0,0,0,0);
dtDateTime = dtDateTime.AddSeconds( unixTimeStamp ).ToLocalTime();
return dtDateTime;
}


var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
Console.WriteLine ( Convert.ToInt64((DateTime.UtcNow - epoch).TotalSeconds));;
Epoch time starts on 1 Jan 1970, we get the current UTC time and subtract the date Epoch time starts from, we then convert the value to the total number of seconds that has passed since Epoch time.
Additionally, we convert the value to Int64, as Int32 will no longer be able to store the total number of seconds once we reach 2038.

Related

How can I convert the number of seconds since Jan 1st 1970 into a datetime value?

I have a number that is the number of seconds since January 1st 1970. It was created with this:
var utcNow = (int) Math.Truncate(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1)).TotalSeconds);
Now need to convert that number to a date in string form like this:
Tue, Jan 15, 2019
Can someone give me some suggestions on how I can do this. I think I can format it myself but I need a suggestion on how to convert the integer utcNow into a datetime first.

static readonly DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
...
DateTime time = epoch.AddSeconds(utcNow);
You can also use this in reverse:
var seconds = (time - epoch).TotalSeconds;
(which gives a double, but you can cast it to int or long etc)

Some answer are already given, and work. But this is, I believe, the most elegant way of doing it. I'm using DateTimeOffset.FromUnixTimeSeconds(int64)
DateTimeOffset dt = DateTimeOffset.FromUnixTimeSeconds(utcNow);
And now you can convert it into a DateTime Struct with help of this blog entry

Substract the given time from current time and it gives timespan instance, from that you can get total seconds
var fromDate = new DateTime(1970,1 ,1);
var diffrance = DateTime.UtcNow.Subtract(fromDate);
Console.WriteLine(diffrance.TotalSeconds);

Conversion to Unix timestamp is not working

I'm trying to convert DateTime to Unix timestamp.
static long ToUnixTime(DateTime dateTime)
{
var dateTimeOffset = new DateTimeOffset(dateTime);
return dateTimeOffset.ToUnixTimeSeconds();
}
But this function always return timestamp equal to something "Sun Jan 18 1970" instead of current DateTime. What is wrong with this?

The current date as expressed as a Unix timestamp is 1501093539, more or less.
I think you're checking yourself wrong; if I edit my code to add milliseconds, I get 1/18/1970. But unix times aren't in milliseconds. They're in seconds.
var dt = DateTime.Now;
var offset = new DateTimeOffset(dt);
var unix = offset.ToUnixTimeSeconds();
dt = new DateTime(1970,1,1,0,0,0);
dt = dt.AddSeconds(unix);
Debug.WriteLine(dt); // gives current date back
Change it to AddSeconds and you'll get the current date. Change it to AddMilliseconds and you'll get January 18th, 1970. Your code is actually fine.

Here is some code that will give you Unix time stamp with any version of the framework
public static class UnixDateTime
{
private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
public static long GetUnixTimestamp(this DateTime input)
{
return (long)(input - UnixEpoch).TotalSeconds;
}
}
Then just use the extension method
var unixTimeStamp = DateTime.Now.GetUnixTimestamp();

How to avoid loss of precision in .NET for converting from Unix Timestamp to DateTime and back?

Consider the following snippet
var original = new DateTime(635338107839470268);
var unixTimestamp = (original - new DateTime(1970,1,1)).TotalSeconds;
// unixTimestamp is now 1398213983.9470267
var back = new DateTime(1970,1,1).AddSeconds(1398213983.9470267);
// back.Ticks is 635338107839470000
As you can see the Ticks value that we got back is different from what we started with.
How can we avoid this loss of precision in C# while converting from date to unix timestamp and back?

http://msdn.microsoft.com/en-us/library/system.datetime.addseconds.aspx
DateTime.AddSeconds() per the documentation rounds to the nearest millisecond (10,000 ticks).
Using ticks:
// We have a DateTime in memory
DateTime original = new DateTime(635338107839470268);
// We convert it to a Unix Timestamp
double unixTimestamp = (original - new DateTime(1970, 1, 1)).TotalSeconds;
// unixTimestamp is saved somewhere
// User needs to make a 100% precise DateTime from this unix timestamp
DateTime epochInstance = new DateTime(1970, 1, 1);
DateTime back = epochInstance.AddTicks((long)(unixTimestamp * TimeSpan.TicksPerSecond));
// back.Ticks is now 635338107839470268

there is no loss in your timespan, don't compare with TotalSeconds and AddSeconds method results. you need to check for Ticks
var original = new DateTime(635338107839470268);
var Ticks = (original - new DateTime(1970,1,1)).Ticks;
// Ticks is now 13982139839470268
var back = new DateTime(1970,1,1).AddTicks(13982139839470268);
//back.Ticks is 635338107839470268

How can I convert CFAbsoluteTime to DateTime in C#?

Can anyone tell me how can I convert a value which I know to be CFAbsoluteTime from MacOS into DateTime value in C#?

A CFAbsoluteTime is a double, the number of seconds since January 1st, 2001, 12am. Thus:
public static DateTime CFAbsoluteTimeToDateTime(double abs) {
long ticks = (long)(abs * 1E7); // 1 tick == 100 nsec
return new DateTime(new DateTime(2001, 1, 1).Ticks + ticks);
}

It turned out, that I can convert it using following code:
TimeSpan span = TimeSpan.FromSeconds(CFAbsoluteTimeFloatValue);
var cshartpDateTime = new DateTime(2001, 1, 1).Add(span);

DateTime to javascript date

From another answer on Stackoverflow is a conversion from Javascript date to .net DateTime:
long msSinceEpoch = 1260402952906; // Value from Date.getTime() in JavaScript
return new DateTime(1970, 1, 1) + new TimeSpan(msSinceEpoch * 10000);
But how to do the reverse? DateTime to Javascript Date?

Try:
return DateTime.Now.Subtract(new DateTime(1970, 1,1)).TotalMilliseconds
Edit: true UTC is better, but then we need to be consistent
return DateTime.UtcNow
.Subtract(new DateTime(1970,1,1,0,0,0,DateTimeKind.Utc))
.TotalMilliseconds;
Although, on second thoughts it does not matter, as long as both dates are in the same time zone.

JavaScript Date constructor accepts number of milliseconds since Unix epoch (1 January 1970 00:00:00 UTC). Here’s C# extension method that converts .Net DateTime object to JavaScript date:
public static class DateTimeJavaScript
{
private static readonly long DatetimeMinTimeTicks =
(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).Ticks;
public static long ToJavaScriptMilliseconds(this DateTime dt)
{
return (long)((dt.ToUniversalTime().Ticks - DatetimeMinTimeTicks) / 10000);
}
}
JavaScript Usage:
var dt = new Date(<%= DateTime.Today.ToJavaScriptMilliseconds() %>);
alert(dt);

You can try this in your Action:
return DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ss");
And this in your Ajax success:
success: function (resultDateString) {
var date = new Date(resultDateString);
}
Or this in your View: (Javascript plus C#)
var date = new Date('#DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ss")');

With Moment.js simply use:
var jsDate = moment(netDateTime).toDate();
Where netDateTime is your DateTime variable serialized, something like "/Date(1456956000000+0200)/".

This should do the trick:
date.Subtract(new DateTime(1970, 1,1)).TotalMilliseconds

Another late answer, but this is missing here. If you want to handle conversion of serialized /Date(1425408717000)/ in javascript, you can simply call:
var cSharpDate = "/Date(1425408717000)/"
var jsDate = new Date(parseInt(cSharpDate.replace(/[^0-9 +]/g, '')));
Source: amirsahib

I know this is a little late, but here's the solution I had to come up with for handling dates when you want to be timezone independent. Essentially it involves converting everything to UTC.
From Javascript to Server:
Send out dates as epoch values with the timezone offset removed.
var d = new Date(2015,0,1) // Jan 1, 2015
// Ajax Request to server ...
$.ajax({
url: '/target',
params: { date: d.getTime() - (d.getTimezoneOffset() * 60 * 1000) }
});
The server then recieves 1420070400000 as the date epoch.
On the Server side, convert that epoch value to a datetime object:
DateTime d = new DateTime(1970, 1, 1, 0, 0, 0).AddMilliseconds(epoch);
At this point the date is just the date/time provided by the user as they provided it. Effectively it is UTC.
Going the other way:
When the server pulls data from the database, presumably in UTC, get the difference as an epoch (making sure that both date objects are either local or UTC):
long ms = (long)utcDate.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
or
long ms = (long)localDate.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Local)).TotalMilliseconds;
When javascript receives this value, create a new date object. However, this date object is going to be assumed local time, so you need to offset it by the current timezone:
var epochValue = 1420070400000 // value pulled from server.
var utcDateVal = new Date(epochValue);
var actualDate = new Date(utcDateVal.getTime() + (utcDateVal.getTimezoneOffset() * 60 * 1000))
console.log(utcDateVal); // Wed Dec 31 2014 19:00:00 GMT-0500 (Eastern Standard Time)
console.log(actualDate); // Thu Jan 01 2015 00:00:00 GMT-0500 (Eastern Standard Time)
As far as I know, this should work for any time zone where you need to display dates that are timezone independent.

This method is working for me:
public sCdateToJsDate(cSDate: any): Date {
// cSDate is '2017-01-24T14:14:55.807'
var datestr = cSDate.toString();
var dateAr = datestr.split('-');
var year = parseInt(dateAr[0]);
var month = parseInt(dateAr[1])-1;
var day = parseInt(dateAr[2].substring(0, dateAr[2].indexOf("T")));
var timestring = dateAr[2].substring(dateAr[2].indexOf("T") + 1);
var timeAr = timestring.split(":");
var hour = parseInt(timeAr[0]);
var min = parseInt(timeAr[1]);
var sek = parseInt(timeAr[2]);
var date = new Date(year, month, day, hour, min, sek, 0);
return date;
}

If you use MVC with razor
-----Razor/C#
var dt1 = DateTime.Now.AddDays(14).Date;
var dt2 = DateTime.Now.AddDays(18).Date;
var lstDateTime = new List<DateTime>();
lstDateTime.Add(dt1);
lstDateTime.Add(dt2);
---Javascript
$(function() {
var arr = []; //javascript array
#foreach (var item in lstDateTime)
{
#:arr1.push(new Date(#item.Year, #(item.Month - 1), #item.Day));
}
1: create the list in C# and fill it
2: Create an array in javascript
3: Use razor to iterate the list
4: Use #: to switch back to js and # to switch to C#
5: The -1 in the month to correct the month number in js.
Good luck

I did this using date time format.
C# to JS
public static class DateTimeExtension
{
public static string ToJsString(this DateTime #this)
{
return #this.ToString("ddd, dd MMM yyyy HH:mm:ss") + " GMT";
}
}
JS to C#
public DateTime ParseJSDate(this string jsDate)
{
return DateTime.ParseExact(jsDate, "ddd, dd MMM yyyy HH:mm:ss GMT", CultureInfo.InvariantCulture);
}

<input type="hidden" id="CDate" value="<%=DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss")%>" />
In order to convert the date to JS date(all numbers):
var JSDate = $("#CDate").val();
JSDate = Date.parse(JSDate);

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