Access to COM Port denied

Whenever I try and access a COM Port  Open control that has been declared on a previous form it give me the following error. Access to the port COM20 is denied.
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cmdolcetConnect With a Mentor Author Commented:
After I reviewed the code I noticed that my COM Port was always open and I need to close the COM Port connection before I could open the new one up. That's where the error came from.
Could you perhaps provide some code to review?

cmdolcetAuthor Commented:
I go through this the first sub and open the port (btnFindButton_Click). I return all the values on that open port. I then press the btnChangeChannel  to open the second form. I  assign a value to  the RF_Selected variable in that second form  (which is a global variable) and then close the form. However before closing I call thebtnFindButton_Click(nothing, nothing) which puts me into the btnFindButton_Click again and I look to see if my variable state has changed (WirelessBase_RF_CH_Changed= True) If it changed then I try to write to the COM port  serialCOMDiscover.Write(" <#B" & RF_Selected) this is when it guives me the error.
Public Sub btnFindButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFindButton2.Click 
For intloop = 0 To ActiveCOM.Count - 1
            'set the properties of the com port
            serialCOMDiscover.PortName = "COM" & ActiveCOM(intloop)
            Selected_COM_Port = ActiveCOM(intloop)
            serialCOMDiscover.BaudRate = 9600
            serialCOMDiscover.Parity = Parity.None
            serialCOMDiscover.DataBits = 8
            serialCOMDiscover.DtrEnable = True
            If WirelessBase_RF_CH_Changed = False Then
                serialCOMDiscover.Write(" <#B" & RF_Selected)
            End If
            strDataCOM1 = serialCOMDiscover.ReadExisting
end sub

 Private Sub btnChangeChannel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnChangeChannel.Click
        Dim frmChannelChange As New frmChannelUpdate
    End Sub

Open in new window

1.) Maybe the SerialPort does not like it, if you change the PortName and Write data directly afterwards ;-)

2.) What happens in the first run? Do you write data to the COM port in line 17 without opening it first?
cmdolcetAuthor Commented:
after reviewing the code I noticed that I was not closing my COM port before opening up the same COM port. My mistake
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