[c#] How does DateTime.Now.Ticks exactly work?

In my application I generate files at random opportunities. To ensure a unique naming, I tried to use the nano seconds since 1.1.1970:

long time = DateTime.Now.Ticks;
String fileName = Convert.ToString(time);
Console.WriteLine(fileName);

Now I observed something weird. Why is the output like that? I mean why are the last 4 numbers always the same? I can use this as a filename, that is not the problem, but I'm just wondering about it.

634292263478068039
634292263512888039
634292263541368039
634292263603448039
634292263680078039

to convert the current datetime to file name to save files you can use

DateTime.Now.ToFileTime();

this should resolve your objective

You can get the milliseconds since 1/1/1970 using such code:

private static DateTime JanFirst1970 = new DateTime(1970, 1, 1);
public static long getTime()
{
    return (long)((DateTime.Now.ToUniversalTime() - JanFirst1970).TotalMilliseconds + 0.5);
}

Not really an answer to your question as asked, but thought I'd chip in about your general objective.

There already is a method to generate random file names in .NET.

See System.Path.GetTempFileName and GetRandomFileName.

Alternatively, it is a common practice to use a GUID to name random files.

I had a similar problem.

I would also look at this answer: Is there a high resolution (microsecond, nanosecond) DateTime object available for the CLR?.

About half-way down is an answer by "Robert P" with some extension functions I found useful.