Using ActiveXperts Serial Port Component with with ASP.NET VB.NET (Visual Basic)

Step 2: Create a new ASP.NET VB Project

Launch Microsoft Visual Studio from the Start menu. Choose 'New' from the 'File' menu and click on 'Web Site'. In the 'Web Site' dialog, select ASP.NET VB .NET Web Site. Select a name for the application, we used: 'DemoApp', and a name for the solution, we used: 'DemoSolution'. Finally, select the directory where you want to store the project, for example: 'C:\MyProjects':

Step 3: Refer to the ActiveXperts Serial Port Component Library and create the objects

Now that a new project has been created, you must add a reference to the ActiveXperts Serial Port Component library in the project to be able to use the ActiveXperts Serial Port Component object. To do so, choose 'Add Reference...' from the 'Project' menu. In the 'Add Reference' dialog that pops up, select the 'COM' tab and select the 'Serial Port Component Type Library' as shown in the following picture:

Click 'OK' to close the 'Add Reference' dialog.

On top of your code, type the following line to use the ActiveXperts Serial Port Component namespace:

Imports AxSerial

In your Main function, declare and create the following object:

Dim objComport As ComPort
   
objComPort    = New ComPort()

Step 4: Send an AT command to a Hayes compatible modem

You can now send and/or receive data to and/or from a serial interface.

The following code shows how to query a modem:

Public Class WebForm1
Imports AxSerial

Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub
    Protected WithEvents Button1 As System.Web.UI.WebControls.Button
    Protected WithEvents comboDevice As System.Web.UI.HtmlControls.HtmlSelect
    Protected WithEvents textCommand As System.Web.UI.HtmlControls.HtmlInputText
    Protected WithEvents textResponse As System.Web.UI.HtmlControls.HtmlTextArea
    Protected WithEvents textResult As System.Web.UI.HtmlControls.HtmlTextArea
    Protected WithEvents Form1 As System.Web.UI.HtmlControls.HtmlForm

    'NOTE: The following placeholder declaration is required by the Web Form Designer.
    'Do not delete or move it.
    Private designerPlaceholderDeclaration As System.Object

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) _
                Handles MyBase.Init
        InitializeComponent()
    End Sub

#End Region

    Public m_objComPort As ComPort

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) _
                Handles MyBase.Load

        Dim i As System.Int32

        m_objComPort = New ComPort()
        comboDevice.Items.Clear()

        For i = 0 To m_objComPort.GetDeviceCount - 1
            comboDevice.Items.Add(m_objComPort.GetDevice(i))
        Next

        For i = 1 To 8
            comboDevice.Items.Add("COM" + i.ToString())
        Next

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
                Handles Button1.Click

        Dim LastError

        m_objComPort.Device = Request.Form(comboDevice.UniqueID)
        m_objComPort.BaudRate = 9600
        m_objComPort.ComTimeout = 500
        m_objComPort.LogFile = "C:\ComLog.txt"
        m_objComPort.Open()

        LastError = m_objComPort.LastError

        If (LastError = 0) Then
            textResult.Value = "SUCCESS"
        Else
            textResult.Value = "ERROR " & LastError & " ( " & _ 
              m_objComPort.GetErrorDescription(LastError) & " )"
        End If

        If (m_objComPort.IsOpened = -1) Then
            m_objComPort.WriteString(textCommand.Value)
            textResponse.Value = ""
            While (m_objComPort.LastError = 0)
                textResponse.Value += m_objComPort.ReadString() + vbCrLf
            End While
            m_objComPort.Close()
        End If
    End Sub
End Class

You can download the full samples here.