Public Class Main
 
    Private Test As New Test
    Private Delegate Sub SetTextDlg(ByVal text As String)
 
    Private Sub Main_Load([...]) Handles MyBase.Load
        Me.CreateHandle()
        Test.StartThread()
    End Sub
 
    Private Sub Change(ByVal text As String)
        test_TSMI.Text = text
        test_TSMI.Owner.Refresh
    End Sub
 
    Public Sub SetText1(ByVal text As String)
        If test_TSMI.Owner.InvokeRequired = True Then
            test_TSMI.Owner.Invoke(New SetTextDlg(AddressOf SetText), New   _
              Object() {text})
        Else
            test_TSMI.Text = text
            test_TSMI.Owner.Refresh
        End if
    End Sub
 
    Public Sub SetText2(ByVal text As String)
        test_TSMI.Owner.Invoke(New SetTextDlg(AddressOf Change), New   Object() _
          {text})
    End Sub
End Class
 
Public Class Test
 
    Private TestThread As Thread
 
    Public Sub StartThread()
        TestThread = New Thread(AddressOf ChangeTSMI)
        TestThread.Start()
    End Sub
 
    Private Sub ChangeTSMI()
        Main.SetText1("Test")
        Main.SetText2("Test")
    End Sub
End Class