[RESOLVED] a tale of two timers

[vbforever23]

Hi folks.

I have a form with a label. I want the form to display a message every 5 seconds, and the message to display for 700ms before closing. So I used timer1 with an interval of 5000ms, and timer2 with an interval of 700ms. But the message seems to be displaying every 5 seconds(what I want), but is displayed for 5 seconds(what I don't want). I want the message to display only for 700ms. Where is the problem in the code? Thanks in advance.

Public Class Form1

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer2.Start()
    End Sub

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        If Me.Visible = True Then
            Me.Visible = False
        Else
            Me.Visible = True
            Me.Label1.Text = "Test Message"
        End If
        Timer2.Stop()
    End Sub
End Class

[szlamany]

Try using a single timer running often enough to do both jobs of turning on and turning off the message.

Retain the last time turned on so you can manage the on/off.

[vbforever23]

Thanks for your reply. I will give your suggestion a go, but before that, could you explain why my program displays the message for 5 seconds, instead of 7/10 of a second? I am looking at my code, and I just can't figure out this strange behaviour. Thank you.

[si_the_geek]

It is because you have explicitly tied the speed to Timer1.

Each time Timer1 fires, you start Timer2. When Timer2 fires, you do the work and disable Timer2 - and then have to wait until Timer1 starts it again.

The simplest solution is to make two changes (add a line, and move one):

Public Class Form1

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer2.Start()
        Timer1.Stop() 
    End Sub

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        If Me.Visible = True Then
            Me.Visible = False
            Timer2.Stop()
        Else
            Me.Visible = True
            Me.Label1.Text = "Test Message"
        End If
    End Sub
End Class

szlamany's suggestion is more elegant and self-contained, but takes a bit more code... this is one way it could be done (with just Timer1):

Public Class Form1

    Private TimerStartedAt as Date

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        TimerStartedAt = Now() 
        Timer1.Interval = 100
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Select Case (Now - TimerStartedAt).TotalMilliseconds
        Case 5000 To 5700
            If Not Me.Visible Then
                Me.Visible = True
                Me.Label1.Text = "Test Message"
            End If
        Case > 5700
            Me.Visible = False
            Timer1.Stop()
        End Select
    End Sub
End Class