There is this example code, but then it starts talking about millisecond / nanosecond problems.
The same question is on MSDN, Seconds since the Unix epoch in C#.
This is what I've got so far:
public Double CreatedEpoch
{
get
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
TimeSpan span = (this.Created.ToLocalTime() - epoch);
return span.TotalSeconds;
}
set
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
this.Created = epoch.AddSeconds(value);
}
}
This question is related to
c#
datetime
unix
epoch
data-conversion
From Wikipedia:
UTC does not change with a change of seasons, but local time or civil time may change if a time zone jurisdiction observes daylight saving time (summer time). For example, local time on the east coast of the United States is five hours behind UTC during winter, but four hours behind while daylight saving is observed there.
So this is my code:
TimeSpan span = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0,DateTimeKind.Utc));
double unixTime = span.TotalSeconds;
DateTime to UNIX timestamp:
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
return (TimeZoneInfo.ConvertTimeToUtc(dateTime) -
new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc)).TotalSeconds;
}
For .NET 4.6 and later:
public static class UnixDateTime
{
public static DateTimeOffset FromUnixTimeSeconds(long seconds)
{
if (seconds < -62135596800L || seconds > 253402300799L)
throw new ArgumentOutOfRangeException("seconds", seconds, "");
return new DateTimeOffset(seconds * 10000000L + 621355968000000000L, TimeSpan.Zero);
}
public static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
{
if (milliseconds < -62135596800000L || milliseconds > 253402300799999L)
throw new ArgumentOutOfRangeException("milliseconds", milliseconds, "");
return new DateTimeOffset(milliseconds * 10000L + 621355968000000000L, TimeSpan.Zero);
}
public static long ToUnixTimeSeconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000000L - 62135596800L;
}
public static long ToUnixTimeMilliseconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000L - 62135596800000L;
}
[Test]
public void UnixSeconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInSeconds = utcNowOffset.ToUnixTimeSeconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeSeconds(unixTimestampInSeconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
}
[Test]
public void UnixMilliseconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInMilliseconds = utcNowOffset.ToUnixTimeMilliseconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeMilliseconds(unixTimestampInMilliseconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
Assert.AreEqual(utcNowOffset.Millisecond, utcNowOffsetTest.Millisecond);
}
}
The latest version of .NET (v4.6) has added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
DateTimeOffset
:DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset
to Unix time in seconds:long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
DateTimeOffset
:DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset
to Unix time in milliseconds:long unixTimeStampInMilliseconds = dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from a UTC DateTimeOffset
. To get a DateTime
representation simply use the DateTimeOffset.UtcDateTime
or DateTimeOffset.LocalDateTime
properties:
DateTime dateTime = dateTimeOffset.UtcDateTime;
Be careful, if you need precision higher than milliseconds!
.NET (v4.6) methods (e.g. FromUnixTimeMilliseconds) don't provide this precision.
AddSeconds and AddMilliseconds also cut off the microseconds in the double.
These versions have high precision:
Unix -> DateTime
public static DateTime UnixTimestampToDateTime(double unixTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (long) (unixTime * TimeSpan.TicksPerSecond);
return new DateTime(unixStart.Ticks + unixTimeStampInTicks, System.DateTimeKind.Utc);
}
DateTime -> Unix
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (dateTime.ToUniversalTime() - unixStart).Ticks;
return (double) unixTimeStampInTicks / TimeSpan.TicksPerSecond;
}
See IdentityModel.EpochTimeExtensions
public static class EpochTimeExtensions
{
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTime dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTimeOffset dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given epoch time to a <see cref="DateTime"/> with <see cref="DateTimeKind.Utc"/> kind.
/// </summary>
public static DateTime ToDateTimeFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).AddTicks(timeInTicks);
}
/// <summary>
/// Converts the given epoch time to a UTC <see cref="DateTimeOffset"/>.
/// </summary>
public static DateTimeOffset ToDateTimeOffsetFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).AddTicks(timeInTicks);
}
}
var dt = DateTime.Now;
var unixTime = ((DateTimeOffset)dt).ToUnixTimeSeconds();
// 1510396991
var dt = DateTimeOffset.FromUnixTimeSeconds(1510396991);
// [11.11.2017 10:43:11 +00:00]
From .net 4.6, you can do this:
var dateTime = DateTimeOffset.FromUnixTimeSeconds(unixDateTime).DateTime;
To supplement ScottCher's answer, I recently found myself in the annoying scenario of having both seconds and milliseconds UNIX timestamps arbitrarily mixed together in an input data set. The following code seems to handle this well:
static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
static readonly double MaxUnixSeconds = (DateTime.MaxValue - UnixEpoch).TotalSeconds;
public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
{
return unixTimeStamp > MaxUnixSeconds
? UnixEpoch.AddMilliseconds(unixTimeStamp)
: UnixEpoch.AddSeconds(unixTimeStamp);
}
From Wikipedia:
UTC does not change with a change of seasons, but local time or civil time may change if a time zone jurisdiction observes daylight saving time (summer time). For example, local time on the east coast of the United States is five hours behind UTC during winter, but four hours behind while daylight saving is observed there.
So this is my code:
TimeSpan span = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0,DateTimeKind.Utc));
double unixTime = span.TotalSeconds;
You can use DateTimeOffset.
For example. I have DateTime object
var dateTime1=DateTime.Now;
If I want convert the it to Unix time stamps, I can be achieve as follows
var unixTimeSeconds= new DateTimeOffset(dateTime1).ToUnixTimeSeconds()
If you want convert unix timeStamp to normal DateTime, you can use this code piece:
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).LocalDateTime;
or
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).UtcDateTime;
For more information please visit this link :
DateTimeOffset.ToUnixTimeSeconds Method,
DateTimeOffset.FromUnixTimeSeconds
Unix time conversion is new in .NET Framework 4.6.
You can now more easily convert date and time values to or from .NET Framework types and Unix time. This can be necessary, for example, when converting time values between a JavaScript client and .NET server. The following APIs have been added to the DateTimeOffset structure:
static DateTimeOffset FromUnixTimeSeconds(long seconds)
static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
long DateTimeOffset.ToUnixTimeSeconds()
long DateTimeOffset.ToUnixTimeMilliseconds()
You can use DateTimeOffset.
For example. I have DateTime object
var dateTime1=DateTime.Now;
If I want convert the it to Unix time stamps, I can be achieve as follows
var unixTimeSeconds= new DateTimeOffset(dateTime1).ToUnixTimeSeconds()
If you want convert unix timeStamp to normal DateTime, you can use this code piece:
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).LocalDateTime;
or
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).UtcDateTime;
For more information please visit this link :
DateTimeOffset.ToUnixTimeSeconds Method,
DateTimeOffset.FromUnixTimeSeconds
System.DateTimeOffset.Now.ToUnixTimeSeconds()
I needed to convert a timeval struct (seconds, microseconds) containing UNIX time
to DateTime
without losing precision and haven't found an answer here so I thought I just might add mine:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
To supplement ScottCher's answer, I recently found myself in the annoying scenario of having both seconds and milliseconds UNIX timestamps arbitrarily mixed together in an input data set. The following code seems to handle this well:
static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
static readonly double MaxUnixSeconds = (DateTime.MaxValue - UnixEpoch).TotalSeconds;
public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
{
return unixTimeStamp > MaxUnixSeconds
? UnixEpoch.AddMilliseconds(unixTimeStamp)
: UnixEpoch.AddSeconds(unixTimeStamp);
}
public static class UnixTime
{
private static readonly DateTime Epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
public static DateTime UnixTimeToDateTime(double unixTimeStamp)
{
return Epoch.AddSeconds(unixTimeStamp).ToUniversalTime();
}
}
you can call UnixTime.UnixTimeToDateTime(double datetime))
System.DateTimeOffset.Now.ToUnixTimeSeconds()
DateTime to UNIX timestamp:
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
return (TimeZoneInfo.ConvertTimeToUtc(dateTime) -
new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc)).TotalSeconds;
}
var dt = DateTime.Now;
var unixTime = ((DateTimeOffset)dt).ToUnixTimeSeconds();
// 1510396991
var dt = DateTimeOffset.FromUnixTimeSeconds(1510396991);
// [11.11.2017 10:43:11 +00:00]
I found the right answer just by comparing the conversion to 1/1/1970 w/o the local time adjustment;
DateTime date = new DateTime(2011, 4, 1, 12, 0, 0, 0);
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan span = (date - epoch);
double unixTime =span.TotalSeconds;
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
I found the right answer just by comparing the conversion to 1/1/1970 w/o the local time adjustment;
DateTime date = new DateTime(2011, 4, 1, 12, 0, 0, 0);
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan span = (date - epoch);
double unixTime =span.TotalSeconds;
Written a simplest extension that works for us. If anyone looks for it...
public static class DateTimeExtensions
{
public static DateTime FromUnixTimeStampToDateTime(this string unixTimeStamp)
{
return DateTimeOffset.FromUnixTimeSeconds(long.Parse(unixTimeStamp)).UtcDateTime;
}
}
I needed to convert a timeval struct (seconds, microseconds) containing UNIX time
to DateTime
without losing precision and haven't found an answer here so I thought I just might add mine:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
Written a simplest extension that works for us. If anyone looks for it...
public static class DateTimeExtensions
{
public static DateTime FromUnixTimeStampToDateTime(this string unixTimeStamp)
{
return DateTimeOffset.FromUnixTimeSeconds(long.Parse(unixTimeStamp)).UtcDateTime;
}
}
public static class UnixTime
{
private static readonly DateTime Epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
public static DateTime UnixTimeToDateTime(double unixTimeStamp)
{
return Epoch.AddSeconds(unixTimeStamp).ToUniversalTime();
}
}
you can call UnixTime.UnixTimeToDateTime(double datetime))
See IdentityModel.EpochTimeExtensions
public static class EpochTimeExtensions
{
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTime dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTimeOffset dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given epoch time to a <see cref="DateTime"/> with <see cref="DateTimeKind.Utc"/> kind.
/// </summary>
public static DateTime ToDateTimeFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).AddTicks(timeInTicks);
}
/// <summary>
/// Converts the given epoch time to a UTC <see cref="DateTimeOffset"/>.
/// </summary>
public static DateTimeOffset ToDateTimeOffsetFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).AddTicks(timeInTicks);
}
}
The latest version of .NET (v4.6) has added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
DateTimeOffset
:DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset
to Unix time in seconds:long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
DateTimeOffset
:DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset
to Unix time in milliseconds:long unixTimeStampInMilliseconds = dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from a UTC DateTimeOffset
. To get a DateTime
representation simply use the DateTimeOffset.UtcDateTime
or DateTimeOffset.LocalDateTime
properties:
DateTime dateTime = dateTimeOffset.UtcDateTime;
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
DateTime unixEpoch = DateTime.ParseExact("1970-01-01", "yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
DateTime convertedTime = unixEpoch.AddMilliseconds(unixTimeInMillisconds);
Of course, one can make unixEpoch
a global static, so it only needs to appear once in your project, and one can use AddSeconds
if the UNIX time is in seconds.
To go the other way:
double unixTimeInMilliseconds = timeToConvert.Subtract(unixEpoch).TotalMilliseconds;
Truncate to Int64 and/or use TotalSeconds
as needed.
Be careful, if you need precision higher than milliseconds!
.NET (v4.6) methods (e.g. FromUnixTimeMilliseconds) don't provide this precision.
AddSeconds and AddMilliseconds also cut off the microseconds in the double.
These versions have high precision:
Unix -> DateTime
public static DateTime UnixTimestampToDateTime(double unixTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (long) (unixTime * TimeSpan.TicksPerSecond);
return new DateTime(unixStart.Ticks + unixTimeStampInTicks, System.DateTimeKind.Utc);
}
DateTime -> Unix
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (dateTime.ToUniversalTime() - unixStart).Ticks;
return (double) unixTimeStampInTicks / TimeSpan.TicksPerSecond;
}
For .NET 4.6 and later:
public static class UnixDateTime
{
public static DateTimeOffset FromUnixTimeSeconds(long seconds)
{
if (seconds < -62135596800L || seconds > 253402300799L)
throw new ArgumentOutOfRangeException("seconds", seconds, "");
return new DateTimeOffset(seconds * 10000000L + 621355968000000000L, TimeSpan.Zero);
}
public static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
{
if (milliseconds < -62135596800000L || milliseconds > 253402300799999L)
throw new ArgumentOutOfRangeException("milliseconds", milliseconds, "");
return new DateTimeOffset(milliseconds * 10000L + 621355968000000000L, TimeSpan.Zero);
}
public static long ToUnixTimeSeconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000000L - 62135596800L;
}
public static long ToUnixTimeMilliseconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000L - 62135596800000L;
}
[Test]
public void UnixSeconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInSeconds = utcNowOffset.ToUnixTimeSeconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeSeconds(unixTimestampInSeconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
}
[Test]
public void UnixMilliseconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInMilliseconds = utcNowOffset.ToUnixTimeMilliseconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeMilliseconds(unixTimestampInMilliseconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
Assert.AreEqual(utcNowOffset.Millisecond, utcNowOffsetTest.Millisecond);
}
}
DateTime unixEpoch = DateTime.ParseExact("1970-01-01", "yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
DateTime convertedTime = unixEpoch.AddMilliseconds(unixTimeInMillisconds);
Of course, one can make unixEpoch
a global static, so it only needs to appear once in your project, and one can use AddSeconds
if the UNIX time is in seconds.
To go the other way:
double unixTimeInMilliseconds = timeToConvert.Subtract(unixEpoch).TotalMilliseconds;
Truncate to Int64 and/or use TotalSeconds
as needed.
Unix time conversion is new in .NET Framework 4.6.
You can now more easily convert date and time values to or from .NET Framework types and Unix time. This can be necessary, for example, when converting time values between a JavaScript client and .NET server. The following APIs have been added to the DateTimeOffset structure:
static DateTimeOffset FromUnixTimeSeconds(long seconds)
static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
long DateTimeOffset.ToUnixTimeSeconds()
long DateTimeOffset.ToUnixTimeMilliseconds()
Source: Stackoverflow.com