Hi, everyone! i got some problem about vb.net Serial port, hope you guys can help me

i want to write a program to receive hex code from machine. The machine non stop every second send out 48byte hex code.
so i need to capture all 48 hex code per second. the hex look like below:

986700272700000000800080000000000000000000000000986800272700000000800002000000000000000000000000

how can i receive all 48 hex code, and show in textbox1?
and then how can i capture 10th, 11th and 12th hex code show in textbox2?

i'm write the code can capture the hex code but cant store complete 48 byte hex code.
here is my vb.net code:
Code:
Private Sub SerialPort1_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        UpdateFormDelegate1 = New UpdateFormDelegate(AddressOf UpdateDisplay)
        Dim n As Integer = SerialPort1.BytesToRead 'find number of bytes in buf
        comBuffer = New Byte(n - 1) {} 're dimension storage buffer
        SerialPort1.Read(comBuffer, 0, n) 'read data from the buffer
        Me.Invoke(UpdateFormDelegate1) 'call the delegate   
    End Sub

    Private Sub UpdateDisplay()
        On Error GoTo handle
        Dim num1, num2, num3, str1, str2, str3 As String
        Dim lngpos As Long
        num2 = ""
        For i = LBound(comBuffer) To UBound(comBuffer)
            num1 = Hex(comBuffer(i))
            If Len(num1) = 1 Then
                num2 = "0" & num1
            Else
                num2 = num1
            End If
        Next

        TextBox1.Text &= num2 'store all hex code
        num3 = TextBox1.Text
        lngpos = InStr(num3, 80)
        str1 = Mid$(num3, lngpos, 6)
        TextBox2.Text = str1 
end sub
please help me.

thank!