vb.net event handle not working - vb.net

Question

I am new in vb.net, I have a data collection application that use scan data in warehouse. it is window system, I couldn't get the event handling work. Please help me find what is wrong with my program below.
Here is the project, In the app I have a scanner class that I use it to scan barcode, and when scan happens raise an event to let the forms know. many forms can use scan data. But only the form visible on top will handle the scanned data.
I have 2 forms order form and ticket form, they both handle the scandata event. First order form handles scan data event and fill in the scanned order text field, then it automatically launches ticket form, and the ticket form suppose to handle the scan data event and post data on ticket form.
The Order form handles the event fine, the problem is after launching the ticket form automatically, it seems cannot associate to the event, the event seems still with the Order forms, So,ticket form not reveiving it and does nothing.
I have to use LaunchTickets() in order form to get to ticket due to business request, How do I implement this to get the event associate to correct form whatever the form visible on top in my application? I don't know if there is a way to get around, if not, what is the best way to implement this? please help me to get this work.
Public Class ClsComPort
Public Shared Event NewScanData(ByVal ScanData As String)
Public Function InitializebcrScanner() As Boolean
AddHandler mySerialPort.DataReceived, AddressOf mySerialPort_DataReceived
End Function
Private Sub mySerialPort_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
'omitted steps to get the scanned data
ScanData = str.Trim()
RaiseEvent NewScanData(scandata) 'raise the scan event
End sub end class
Public Class frmOrder
Friend WithEvents scanner As New ClsComPort
Private Sub GetScanData(ByVal ScanData As String) Handles scanner.NewScanData
txtOrder.Text = ScanData 'this runs ok, I got the scan data in this field
LaunchTickets() 'App automatically go to next form- ticket form, this seems to cause the event handling issue
End Sub
Private Sub LaunchTickets()
Me.Visible = False
frmTickets.WindowState = FormWindowState.Maximized
frmTickets.ShowDialog()
Me.Visible = True
End Sub
End Class
Public Class frmticket
Friend WithEvents scanner As New ClsComPort
Private Sub GetScanData(ByVal ScanData As String) Handles scanner.NewScanData
txtTicket.Text = ScanData
'not working, just nothing happen, and when back to order form, program crashed
End Sub
End Class

Answer 1

When you make the instance of the frmticket class you are subscribing to your custom event, but that event only fires when the DataReceived event fires and that is not wired up until you call InitializebcrScanner(you did not call it) - which should be a Sub not a Function since you do not return a boolean value or need to. Make an instance of the form not the default instance.
Private Sub LaunchTickets()
Me.Visible = False
Dim ticketsForm As New frmTickets
ticketsForm.WindowState = FormWindowState.Maximized
ticketsForm.ShowDialog()
Me.Visible = True
End Sub
This:
Public Function InitializebcrScanner() As Boolean
AddHandler mySerialPort.DataReceived, AddressOf mySerialPort_DataReceived
End Function
Should be in the constructor:
Sub New()
AddHandler mySerialPort.DataReceived, AddressOf mySerialPort_DataReceived
End Sub