Timed function call

Hey! I want my app to do a backup save at a specified time(e.g 01:00 AM) everyday. How can I time my function to be called every night at 01:00, without timer, or isn't it possible ?I think the nonstop timer ticking would slow the app. My application'll be running non-stop.

Something like this might work

Code:

---

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim t As Task
        t = Task.Run(Sub()
                        Do
                            Dim whenToRun As TimeSpan
                            'calculate when to run approx.
                            whenToRun = DateTime.Now.Date.AddDays(1).AddHours(1).AddSeconds(-15) - DateTime.Now
                            Threading.Thread.Sleep(whenToRun)
                            While DateTime.Now.Hour < 1 'now wait for clock to get to 1
                                Threading.Thread.Sleep(5000) 'set as needed for accuracy
                            End While
                            'backup code here or backup method call
                        Loop
                    End Sub)
    End Sub

---

Technically, that could miss by up to five seconds, but hopefully that won't hurt all that much.

Quote:

---

Originally Posted by David52

without timer, or isn't it possible ?I think the nonstop timer ticking would slow the app.

---

Firstly, no it wouldn't. Secondly, why would there be any non-stop Timer Ticking anyway. Put some thought into it. When you use an alarm clock, does it go off every few seconds so you can check the time and see whether you need to get up? Of course not. You set it to go off once at the exact time you need to get up. Why would you think that it should be any different with a Timer in code? When you start your app, you calculate how long it is until 1.00 AM and that's what yo set the Interval of the Timer to. Once it Ticks, you can either assume that it's accurate and set the Interval to 24 hours or account for any slight drift that may have happened and perform the same calculation again.

The CPU manages waiting in a VERY efficient manner, so don't worry about the cost of waiting for some event to occur. You can assume that there isn't one.