Get time in milliseconds using C#

I'm making a program in which I need to开发者_运维技巧 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?

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();

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

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).

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.

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;
     }
 }

I used DateTime.Now.TimeOfDay.TotalMilliseconds (for current day), hope it helps you out as well.

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

Using Stopwatch class we can achieve it from System.Diagnostics.

Stopwatch stopwatch  = new Stopwatch();
stopwatch.Start();
stopwatch.Stop();
Debug.WriteLine(stopwatch.ElapsedMilliseconds);

System.DateTimeOffset.Now.ToString("MM/dd/yyyy hh:mm:ss.fff tt") to get the millisecond in the format of '04/01/2021 04:32:14.788 PM'

https://learn.microsoft.com/en-us/dotnet/standard/base-types/how-to-display-milliseconds-in-date-and-time-values

As I understand your requirements Environment.TickCount fits the bill. It returns number of milliseconds since startup, so it always increases and can be used for computing elapsed time in milliseconds. If you want absolute time also, you can get current time and current Environment.TickCount, and compute new absolute time based on that and new Environment.TickCount.