c# - Why is the data type of System.Timers.Timer.Interval a double?

Question

This is a bit of an academic question as I'm struggling with the thinking behind Microsoft using double as the data type for the Interval property!

Firstly from MDSN Interval is the time, in milliseconds, between Elapsed events; I would interpret that to be a discrete number so why the use of a double? surely int or long makes greater sense!?

Can Interval support values like 5.768585 (5.768585 ms)? Especially when one considers System.Timers.Timer to have nowhere near sub millisecond accuracy... Most accurate timer in .NET?

Seems a bit daft to me.. Maybe I'm missing something!

Answer 1

Disassembling shows that the interval is consumed via a call to (int)Math.Ceiling(this.interval) so even if you were to specify a real number, it would be turned into an int before use. This happens in a method called UpdateTimer.

Why? No idea, perhaps the spec said that double was required at one point and that changed? The end result is that double is not strictly required, because it is eventually converted to an int and cannot be larger than Int32.MaxValue according to the docs anyway.

Yes, the timer can "support" real numbers, it just doesn't tell you that it silently changed them. You can initialise and run the timer with 100.5d, it turns it into 101.

And yes, it is all a bit daft: 4 wasted bytes, potential implicit casting, conversion calls, explicit casting, all needless if they'd just used int.