How can I convert a Unix timestamp to DateTime and vice versa?

Question

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);
  }
}

Answer 1

Here's what you need:

public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
{
    // Unix timestamp is seconds past epoch
    DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
    dateTime = dateTime.AddSeconds( unixTimeStamp ).ToLocalTime();
    return dateTime;
}

Or, for Java (which is different because the timestamp is in milliseconds, not seconds):

public static DateTime JavaTimeStampToDateTime( double javaTimeStamp )
{
    // Java timestamp is milliseconds past epoch
    DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
    dateTime = dateTime.AddMilliseconds( javaTimeStamp ).ToLocalTime();
    return dateTime;
}