timer event is not considered

Hi,

can anyone help me understand why after you pressed the button Button1, this application crashes without considering the event timer1??

Code:

---

Public Class Form1
    Public timer_event As Boolean

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        timer_event = False
        Timer1.Interval = 3000 '3 sec
        Timer1.Enabled = True
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
        Timer1.Stop()
        timer_event = True
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Do
            If timer_event Then
                MsgBox(timer_event)
                timer_event = False
                Timer1.Start()
            End If
        Loop
    End Sub
End Class

---

It is not crash, it simply enter an infinite loop, you have to insert DoEvents inside the loop to enable other events fire, Try this

vb Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Do
            If timer_event Then
                MsgBox(timer_event)
                timer_event = False
                Timer1.Start()
            End If
            My.Application.DoEvents()
        Loop
 
    End Sub

You shouldn't have that Do loop in there at all. Get rid of it.

I'd go further than that. You have a timer raising an event when time expires. The only possible purpose for the loop is that you are waiting for that tick event. What's the point of having code running waiting for the event? You are using a flag to signal a different method when the timer ticks, which is wildly inefficient. Just move the code into the tick event itself and get rid of all that is happening in that button click. Let the raising of the event be its own signal.