Fount the soluction:
Public Class Form5
Delegate Sub SetTextCallback(ByVal data As String)
Private Delegate Sub UpdateLabelDelegate(theText As String)
Private Sub UpdateLabel(theText As String)
If Me.InvokeRequired Then
Me.Invoke(New UpdateLabelDelegate(AddressOf UpdateLabel), theText)
Else
TextBox1.Text = theText
End If
End Sub
Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim returnStr As String
returnStr = SerialPort1.ReadExisting
Me.BeginInvoke(Sub()
UpdateLabel(returnStr)
End Sub)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
SerialPort1.Open()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
SerialPort1.Close()
End Sub
End Class