Timer1 freezes the UI thread - vb.net

Question

My programm gets a high-speed data from serialport, and timer reads it , after timer gets value , timer is disabled and code does sting operations where add value which accepted earlier from com to listview. THe problem is that UI thread is not completely freezing but it seems laggy when i drag the form also, That code which add +1 every time on the subitem.text - is not smooth.
founditem.SubItems(4).Text = founditem.SubItems(4).Text + 1
Why is that as knows timer creats its own thread, and it shouldnot freeze an UI( i cant get rid of timer, becsouse its neccesary to accept correct data from serial)
Any tips? i tried invoke,begininvoke and background_worker, maybe not correctly.
Also can i call background worker from timer event? I'm not good at asyc tasks. My code is:
Private Sub spOpen()
Try
spClose()
spObj.PortName = "COM4"
spObj.BaudRate = 230400
spObj.Parity = IO.Ports.Parity.None
spObj.DataBits = 8
spObj.StopBits = IO.Ports.StopBits.One
spObj.Handshake = IO.Ports.Handshake.None
spObj.DtrEnable = False 'imp
spObj.RtsEnable = False 'imp
spObj.NewLine = vbCr
spObj.ReadTimeout = 0
spObj.WriteTimeout = 250
spObj.ReceivedBytesThreshold = 1
spObj.Open()
Catch ex As Exception
'catch
End Try
End Sub
Private Sub spClose()
Try
If spObj.IsOpen Then
spObj.Close()
spObj.Dispose()
End If
Catch ex As Exception
'handle the way you want
End Try
End Sub
Function ReverseString(ByVal sText As String) As String
Dim lenText As Long, lPos As Long
If Len(sText) = 0 Then Exit Function
lenText = Len(sText)
ReverseString = Space(lenText)
For lPos = lenText To 1 Step -2
If lPos > 0 Then Mid(ReverseString, lenText - lPos + 1, 2) = Mid(sText, lPos - 1, 2)
If lPos = 0 Then Mid(ReverseString, lenText - lPos + 1, 2) = Mid(sText, lPos, 2)
Next lPos
'Return
End Function
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
'stop the timer (stops this function being called while it is still working
Timer1.Enabled = False
' get any new data and add the the global variable receivedData
receivedData = ReceiveSerialData()
'If receivedData contains a "<" and a ">" then we have data
If ((receivedData.Contains("<") And receivedData.Contains(">"))) Then
'parseData()
first_msg = 1
parseData()
End If
' restart the timer
Timer1.Enabled = True
End Sub
Function ReceiveSerialData() As String
Dim Incoming As String
Try
Incoming = spObj.ReadExisting()
If Incoming Is Nothing Then
Return "nothing" & vbCrLf
Else
Return Incoming
End If
Catch ex As TimeoutException
Return "Error: Serial Port read timed out."
End Try
End Function
Function parseData()
' uses the global variable receivedData
Dim pos1 As Integer
Dim pos2 As Integer
Dim length As Integer
Dim newCommand As String
Dim done As Boolean = False
Dim count As Integer = 0
While (Not done)
pos1 = receivedData.IndexOf("<") + 1
pos2 = receivedData.IndexOf(">") + 1
'occasionally we may not get complete data and the end marker will be in front of the start marker
' for exampe "55><T0056><"
' if pos2 < pos1 then remove the first part of the string from receivedData
If (pos2 < pos1) Then
receivedData = Microsoft.VisualBasic.Mid(receivedData, pos2 + 1)
pos1 = receivedData.IndexOf("<") + 1
pos2 = receivedData.IndexOf(">") + 1
End If
If (pos1 = 0 Or pos2 = 0) Then
' we do not have both start and end markers and we are done
done = True
Else
' we have both start and end markers
length = pos2 - pos1 + 1
If (length > 0) Then
'remove the start and end markers from the command
newCommand = Mid(receivedData, pos1 + 1, length - 2)
' show the command in the text box
RichTextBox1.Text = ""
RichTextBox1.AppendText(newCommand & vbCrLf)
'remove the command from receivedData
receivedData = Mid(receivedData, pos2 + 1)
'RichTextBox1.Text &= receivedData
uart_in = RichTextBox1.Text
data = ""
'RichTextBox2.Text = Mid(RichTextBox1.Text, 6, 3)
'If RichTextBox1.TextLength = 26 Then
can_id = Mid(uart_in, 6, 3) 'extracting and id
dlc = Mid(uart_in, 10, 1)
data = uart_in.Substring(26 - (dlc * 2))
hex2ascii(data)
data = data.InsertEveryNthChar(" ", 2)
' data = ReverseString(data)
Dim articlecheck As String = can_id
Dim founditem As ListViewItem = ListView1.FindItemWithText(articlecheck)
If Not (founditem Is Nothing) Then
founditem.SubItems(0).Text = can_id
founditem.SubItems(1).Text = dlc
' If founditem.SubItems(2).Text <> data Then
' founditem.SubItems(2).ForeColor = Color.LightYellow
founditem.SubItems(2).Text = data
' End If
founditem.SubItems(3).Text = timer_count - founditem.SubItems(3).Text
founditem.SubItems(4).Text = founditem.SubItems(4).Text + 1
founditem.SubItems(5).Text = asciival
' timer_count = 1
first_msg = 0
Else
Dim lvi As New ListViewItem(can_id)
lvi.SubItems.Add(dlc)
lvi.SubItems.Add(data)
lvi.SubItems.Add(timer_count)
lvi.SubItems.Add(count)
lvi.SubItems.Add(asciival)
ListView1.Items.Add(lvi)
End If
End If ' (length > 0)
End If '(pos1 = 0 Or pos2 = 0)
End While
End Function
Function hex2ascii(ByVal hextext As String) As String
Dim a As Integer
Dim y As Integer
Dim value As String
Dim num As String
For y = 1 To Len(hextext) Step 2
num = Mid(hextext, y, 2)
a = Val("&h" & num)
If a = 160 Or a = 0 Or a = 9 Or a = 32 Or a = 11 Then a = 46
value = value & Chr(a)
Next
asciival = value
End Function

Answer 1

Dim System.Threading.Thread yourthread As New System.Threading.Thread(AddressOf yourfunction())
yourthread.Priority = System.Threading.Priority.Highest
yourthread.Start();
you can create a loop in your function and add System.Threading.Thread.Sleep(1000) in the end of the loop to make it work like a timer. You can call all your existing functions through this thread, even the timer.
Be careful while accessing your controls through the thread.
Invoke(Sub() yourcontrol.property = someproperty)