Code for write and read com port on Visual Basic?

ciaramkm

I'm writing a VB code at the moment but I seem to keep getting problems. What I need to do is to read from and write to a com port. What I have in the code so far is just for open and close. Anyone have an idea what code should I use for read and write please?? Also the com port number is 2 hence why it's com2.

Code I have so far is:

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

Dim com2 As IO.Ports.SerialPort = Nothing
com2 = My.Computer.Ports.OpenSerialPort("Com2")

End Sub

Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click

Dim com2 As IO.Ports.SerialPort = Nothing

If com2 IsNot Nothing Then com2.Close()

End Sub

End Class

ciaramkm

Can anyone help me out on this one please ??

Beano

The first link i found on google was this http://www.codeworks.it/net/VBNetRs232.htm

seems to cover what you want to do.

FSL

Why are you defining your com port twice.

Where are you going to initialise the settings, assuming they are not the defaults.


Below is an extract from a VB6 programme which communicated with devices which didn't support handshaking the input was always a fixed length string smaller that the buffer size allocated to the port the output was sent one character at a time the speed of which was controlled by a timer the timer only being enabled when there was anything to output str2 contained the output string, i was initialised as 1 and j set to the length of the string before enabling the timer.

If handshaking is supported then in VB6 you simply used:-
stringvariable = comsdevice.Input
comsdevice.Outpit = stringvariable

There must be similar commands in VB Net

Sub setPorts()

Me.MSComm1.Settings = "9600,n,8,1"
Me.MSComm1.Handshaking = comNone
Me.MSComm1.RTSEnable = True
Me.MSComm1.RThreshold = 1
Me.MSComm1.SThreshold = 1
Me.MSComm1.CommPort = 4
Me.MSComm1.PortOpen = True
Me.MSComm1.DTREnable = True
Me.MSComm2.Settings = "9600,n,8,1"
Me.MSComm2.Handshaking = comNone
Me.MSComm2.RTSEnable = True
Me.MSComm2.RThreshold = 372
Me.MSComm2.InputMode = comInputModeBinary
Me.MSComm2.InBufferSize = 2048
Me.MSComm2.SThreshold = 1
Me.MSComm2.CommPort = 5
Me.MSComm2.PortOpen = True
Me.MSComm2.DTREnable = True
End Sub

Private Sub MSComm2_OnComm()

If Me.MSComm2.CommEvent = comEvReceive Then
buf = MSComm2.Input


rest of code to process input

End Sub

Private Sub Timer1_Timer()


Me.MSComm1.Output = Mid(str2, i, 1)
i = i + 1
If i > j Then
Me.Timer1.Enabled = False
str2 = ""
End If
End Sub