vb.net error : cross-thread operation not valid control 'rtbRecieved' accessed from a thread other than the thread it was created on

Delegate Sub SetTextCallback(ByVal [text] As String)

Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        ReceivedText(SerialPort1.ReadExisting())
    End Sub
    Private Sub ReceivedText(ByVal [text] As String)
        If Me.rtbReceived.InvokeRequired Then
            Dim x As New SetTextCallback(AddressOf ReceivedText)
            Me.Invoke(x, New Object() {(text)})
        Else
            Me.rtbReceived.Text &= [text]

        End If

        DBconnection()

    End Sub

    Private Sub DBconnection()
        Dim myConnection As MySqlConnection
        myConnection = New MySqlConnection("Server=161.246.195.45; User Id = nantawat;Password = 123456; Database = kmitl_database;")
        myConnection.Open()

        Dim intNumRows As Integer
        Dim myCommand As MySqlCommand = myConnection.CreateCommand()
        myCommand.CommandText = "SELECT COUNT(*) FROM dt_in_out WHERE card_id = '" & rtbReceived.Text & "' AND dt_out = '' "
        intNumRows = myCommand.ExecuteScalar()

        If intNumRows > 0 Then
            myCommand.CommandText = "UPDATE dt_in_out SET dt_out = '" & lbTime.Text & "' WHERE card_id = '" & rtbReceived.Text & "' AND dt_out = ''"
            myCommand.CommandType = CommandType.Text
            myCommand.ExecuteNonQuery()
            myConnection.Close()

        Else
            myCommand.CommandText = "INSERT INTO dt_in_out(card_id, dt_in)" & _
                    " VALUES('" & rtbReceived.Text & "','" & lbTime.Text & "')"
            myCommand.CommandType = CommandType.Text
            myCommand.ExecuteNonQuery()
            myConnection.Close()

        End If

        Me.Hide()
        Dim f As New Show_Time
        f.Show()
    End Sub