Can't set focus in custom event handler

Can't set focus in custom event handler

• ShyamD

  Got it. Alex your answer was correct, I was just having some problems implementing it. But it all works now as expected. Thanks for pointing me in the right direction.
  
  
  
  
  

• Ayhan Yerli (TR-NL)

  Okay, that make sense. I made some changes and am now making a call to textBox.invoke, but I keep getting an ArgumentException on the call to invoke. A simplified example of my code looks like this:
  
  Public Class clsReader
  
  Public Event OnRead(ByVal e As System.ComponentModel.CancelEventArgs)
  
  Private Sub ReceiveEvent() Handles SerialPort.OnComm
  rxBuffer = SerialPort.InputArray
  RaiseEvent OnRead(New System.ComponentModel.CancelEventArgs)
  End Sub
  
  ...
  End Class
  
  Public Class myClass
  
  Private WithEvents EIDReader As clsReader
  
  Private Delegate Sub delAddItem()
  
  Public Sub WeHaveARead(ByVal e As System.ComponentModel.CancelEventArgs) Handles EIDReader.OnRead
  Dim del As delAddItem
  del = New delAddItem(AddressOf setFocus)
  ...Do some stuff
  Me.txtBox2.Invoke(del)
  End Sub
  
  Private Sub setFocus()
  ...
  Me.txtBox2.focus
  End Sub
  End Class
  
  I have a couple of questions: 1.) Does .NET CF implement the invoke functionality as I am trying to use it 2.) When I call raiseEvent OnRead does that continue to use the same thread as the Com Port or is it starting a new thread...and does that have anything to do with my error
  
  Thanks for any help.
  
  J-Llo
  
  
  

• Simone1

  Yes, you are missing a call to Invoke. You need to use Textbox.Invoke to call textBox.Focus from a COM port handler since you are on a different thread
  
  
• Can't set focus in custom event handler