Get time in milliseconds using C#

Question

I'm making a program in which I need to get the time in milliseconds. By time, I mean a number that is never equal to itself, and is always 1000 numbers bigger than it was a second ago. I've tried converting DateTime.Now to a TimeSpan and getting the TotalMilliseconds from that... but I've heard it isn't perfectly accurate.

Is there an easier way to do this?

Answer 1

You can try the QueryPerformanceCounter native method. See http://www.pinvoke.net/default.aspx/kernel32/QueryPerformanceCounter.html for more information. This is what the Stopwatch class uses.

See How to get timestamp of tick precision in .NET / C#? for more information.

Stopwatch.GetTimestamp() gives access to this method:

public static long GetTimestamp() {
     if(IsHighResolution) {
         long timestamp = 0;
         SafeNativeMethods.QueryPerformanceCounter(out timestamp);
         return timestamp;
     }
     else {
         return DateTime.UtcNow.Ticks;
     }
 }

Answer 2

Use the Stopwatch class.

Provides a set of methods and properties that you can use to accurately measure elapsed time.

There is some good info on implementing it here:

Performance Tests: Precise Run Time Measurements with System.Diagnostics.Stopwatch

Answer 3

Use System.DateTime.Now.ToUniversalTime(). That puts your reading in a known reference-based millisecond format that totally eliminates day change, etc.

Answer 4

I use the following class. I found it on the Internet once, postulated to be the best NOW().

/// <summary>Class to get current timestamp with enough precision</summary>
static class CurrentMillis
{
    private static readonly DateTime Jan1St1970 = new DateTime (1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
    /// <summary>Get extra long current timestamp</summary>
    public static long Millis { get { return (long)((DateTime.UtcNow - Jan1St1970).TotalMilliseconds); } }
}

Source unknown.

Answer 5

The DateTime.Ticks property gets the number of ticks that represent the date and time.

10,000 Ticks is a millisecond (10,000,000 ticks per second).

Answer 6

long milliseconds = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;

This is actually how the various Unix conversion methods are implemented in the DateTimeOffset class (.NET Framework 4.6+, .NET Standard 1.3+):

long milliseconds = DateTimeOffset.Now.ToUnixTimeMilliseconds();