Timer which can be called from a class and form both - vb.net

Question

I have a simple WinForm application. The main entry point of the application is mainForm. I am using a Timer on the form and the timer interval is being set to 2000ms. The Tick event of the Timer is as below,
Public myValue as Integer = 100
Private Sub myTimer_Tick(sender As Object, e As EventArgs) Handles myTimer.Tick
If myValue = 0 Then
myTimer.Enabled = False
Else
myValue = myValue -1
End If
End Sub
The timer is being called at the start of the application when mainForm is loaded. Now myValue is a global variable and here for the purpose of simplicity I have used this otherwise it is replaced by some process count mechanism which is not required to be explained here.
I am able to use this approach as long as I am using Windows.Forms.Timer placed on some specific Form. I have two more scenarios in which this approach fails.
1 - I have to use the same functionality on some other form and for this currently I am using a separate Timer on another Form and it has its own Tick event.
2 - I have to use the same functionality from another module/class and I am unable to achieve this because for this to work I require a Form.
Now for a start I have looked into Threading.Timer. The problem I am facing is that I don't know how to wait for Threading.Timer to finish as the control goes to next line after Threading.Timer is called. I am not sure whether this can be done with the help of WaitHandle or not. Also I have read that Threading.Timer creates a separate Thread for each of its Tick. This seems like an overkill in my simple scenario.
I just want to use the Timer functionality without the need of Form. Also I could create the similar functionality using a Do Loop with Thread.Sleep inside it but unless I am sure that my Timer functionality is not going to work in other situations I am going to stick to my Timer approach.

Answer 1

I see ... If thats the case, you should really create a second thread that runs a loop. That thread has some exiting parameters that indicates that operation is completed and the Thread itself is set to Isbackground = false.
However, you could also do this ...
Imports System.Timers
Public Class Main
Private Shared WithEvents m_oTimer As Timers.Timer = Nothing
Private Shared m_oWaitHandle_TimerHasCompleted As System.Threading.AutoResetEvent = Nothing
Public Shared Sub Main()
Try
'Application Entry point ...
'Create the global timer
m_oTimer = New Timers.Timer
With m_oTimer
.AutoReset = True
.Interval = 2000
.Start()
End With
'Create the WaitHandle
m_oWaitHandle_TimerHasCompleted = New System.Threading.AutoResetEvent(False)
'Show your form
Dim oFrm As New Form1
Application.Run(oFrm)
'Wait for the timer to also indicate that it has finished before exiting
m_oWaitHandle_TimerHasCompleted.WaitOne()
Catch ex As Exception
'Error Handling here ...
End Try
End Sub
Private Shared Sub m_oTimer_Elapsed(sender As Object, e As ElapsedEventArgs) Handles m_oTimer.Elapsed
'Timer will fire here ...
Try
If 1 = 2 Then
m_oWaitHandle_TimerHasCompleted.Set()
End If
Catch ex As Exception
'Error Handling ...
End Try
End Sub
End Class
Please note that 'm_oWaitHandle_TimerHasCompleted.Set()' will never run, you'll have to add a condition ... however, once run, the WaitOne will complete and the application will exit as required.
Hows zat?

Answer 2

Sounds to me like you want to create a single instance of a timer, that does not need to be instantiated via a form?
If so ... Create a new class called 'Main' and copy the following into it.
Imports System.Timers
Public Class Main
Private Shared WithEvents m_oTimer As Timers.Timer = Nothing
Public Shared Sub Main()
Try
'Application Entry point ...
'Create the global timer
m_oTimer = New Timers.Timer
With m_oTimer
.AutoReset = True
.Interval = 2000
.Start()
End With
'Show your form
Dim oFrm As New Form1
Application.Run(oFrm)
Catch ex As Exception
'Error Handling here ...
End Try
End Sub
Private Shared Sub m_oTimer_Elapsed(sender As Object, e As ElapsedEventArgs) Handles m_oTimer.Elapsed
'Timer will fire here ...
Try
Catch ex As Exception
'Error Handling ...
End Try
End Sub
End Class
Once done, right click on your project and select 'Properties'. In the Application tab you'll see a checkbox called 'Enable Application framework'. Uncheck this box. Now, in the dropdown called 'Startup Object' you should now see 'Sub Main' .... Select that.
When the application runs, Sub Main will now run instead of your form.
This will create the Timer that will fire outside of your form. Please note, as you're not syncing it, I believe it'll run inside a thread so be a little careful there :)