Searching Incoming Serial Data

Question

Greetings!
I was trying to get visual studio to filter through the incoming serial data it is receiving from an Arduino. The program shows the incoming data, so I know the serial port is working, but I'm not sure how to get it to look through that data ( I was thinking
I could use StreamReader to do this). My goal is this: When certain data is received, change the background color of a textbox. I am very new at this and any direction would be appreciated! I feel like i'm throwing spaghetti at a wall... 
Here is my current code:
Imports System
Imports System.Threading
Imports System.IO.Ports
Imports System.ComponentModel
Imports System.IO
Public Class Form1
Dim myPort As Array
Delegate Sub SetTextCallBack(ByVal [TEXT] As String)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
myPort = IO.Ports.SerialPort.GetPortNames()
portCmbo.Items.AddRange(myPort)
End Sub
Private Sub startBtn_Click(sender As Object, e As EventArgs) Handles startBtn.Click
SerialPort1.PortName = portCmbo.Text
SerialPort1.BaudRate = baudCmbo.Text
SerialPort1.Open()
startBtn.Enabled = False
closeBtn.Enabled = True
End Sub
Private Sub closeBtn_Click(sender As Object, e As EventArgs) Handles closeBtn.Click
SerialPort1.Close()
startBtn.Enabled = True
closeBtn.Enabled = False
End Sub
Private Sub SerialPort1_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
ReceivedText(SerialPort1.ReadExisting())
End Sub
Private Sub ReceivedText(ByVal [text] As String)
If Me.inputTxtBox.InvokeRequired Then
Dim x As New SetTextCallBack(AddressOf ReceivedText)
Me.Invoke(x, New Object() {(text)})
Else
Me.inputTxtBox.Text &= [text]
End If
End Sub
Private Sub outputTxtBx_TextChanged(sender As Object, e As EventArgs) Handles outputTxtBx.TextChanged
Dim myReader As StreamReader = New StreamReader("Me.inputTxtBox")
Dim line As String = ""
End Sub
End Class
ps: If there is an easier way of doing this, please let me know!

Answer 1

You should read a good book on "Communications".  When processing received data (from any device) you need to wait until you get the end of message before parsing the data.  The data will be received in chunks that can contain from 1
to a million bytes.  When you get the word "Hello" you could get "H" then "ello" or "Hel" and then "lo".  You can't start looking through the data until you get the entire word "Hello". 
So you first have to define a protocol for sending commands to the device and the amount of data that gets returned.  So normally you have to terminate a message using one of the following methods
1) Ascii : Terminate a message with a fix character like a return or EOM.
2) Ascii or binary : Includes a bytes count at the beginning of the message.
3) Ascii or binary : Each type message is a fixed length.
You can use combination of the 3 methods above.
jdweng