Question

Here Is My Code

Public th As New Thread(New ThreadStart(AddressOf StartFirstPrint))
Public th4 As New Thread(New ThreadStart(AddressOf sendFirstEmail))

Here is the code of StartFirstPrint and sendFirstEmail

Public Sub StartFirstPrint()
  Do While thCont
    Try
      Dim frm As New frmPrint()
      'frm.MdiParent = Me
      frm.StartPrinting()
    Catch ex As Exception
    End Try
  Loop
End Sub

Public Sub sendFirstEmail()
  Do While thCont
    Try
      Dim frmSNDEmail As New frmEmail
      frmSNDEmail.SendEmails()
    Catch ex As Exception
    End Try
  Loop
End Sub

the thCont is a public boolean variable that specifies when to shop those threads.

If I access any control of frmPrint from StartPrinting and any control of frmEmail from SendEmails, will it be thread unsafe call?
StartPrinting is a public Sub of frmPrint and SendEmails is a public Sub of frmEmail

Answer 1

You can not access controls, because you would get an exception because of trying to access controls from a thread not being the thread they are created from. It doesn’t makr a difference that the method is inside the Form – it’s still called from a different thread.