Question

I wrote a VB.NET Windows Service, which works fine. I have only one issue with it. I want the service to execute on the half hour and top of the hour marks (e.g. 9:00, 9:30, 10:00, 10:30, 11:00, etc etc etc). I am using the following code:

Protected Overrides Sub OnStart(ByVal args() As String)
    ' Add code here to start your service. This method should set things
    ' in motion so your service can do its work.
    Dim oCallBack As New TimerCallback(AddressOf TimedEvent)
    oTimer = New System.Threading.Timer(oCallBack, Nothing, 300000, 300000)
    EventLog.WriteEntry("CCFinalizeService has begun successfully." , _
                        System.Diagnostics.EventLogEntryType.Information)

End Sub

This code works, however, if the service starts at, say, 10:15, then it executes at 10:15, 10:45, 11:15, 11:45. How do I make it so it always executes on the 30 minute and top of the hour marks?

Answer 1

You just need to modify the dueTime parameter in the Timer creation method

Dim now As Date = DateTime.Now
Dim dueTime As Integer ' milliseconds to the next half-hour
dueTime = 1800000 - (now.Minute Mod 30) * 60000 - now.Second * 1000 - now.Millisecond
oTimer = New System.Threading.Timer(oCallBack, Nothing, dueTime, 1800000)