Visual Basic .NET Telnet Sample Source Code

ActiveSocket provides an easy-to-use development interface to a variety of IP protocols. By using ActiveSocket, you can very easily create or enhance applications with network features.

ActiveSocket features the following: DNS, FTP, HTTP, HTTPs, ICMP Ping, IP-to-Country, MSN, NTP, RSH, SCP, SFTP, SNMP v1/v2c (Get, GetNext, Set), SNMP Traps, SNMP MIB, SSH, TCP, Telnet, TFTP, UDP, Telnet, Wake-On-LAN and more.

ActiveSocket can be well integrated into .NET environments. This document describes how the ActiveSocket Toolkit can be integrated into into Visual Basic .NET projects.

Step 1: Download and install the ActiveSocket Toolkit

Download the the ActiveSocket Toolkit from the ActiveXperts Download Site and start the installation. The installation guides you through the installation process.

Step 2: Create a new Visual Basic .NET Project

Launch Microsoft Visual Studio (for instance 'Microsoft Visual Studio 2005') from the Start menu. Choose 'New' from the 'File' menu and click on 'Project'. In the 'New Project' dialog, select a Visual Studio template (for instance: 'Console Application'). Select a name for the application (for instance: 'DemoApp') and a name for the solution (for instance: 'DemoSolution'). Also, select the directory where you want to store the project (for instance: 'C:\MyProjects):

(Click on the picture to enlarge)

Step 3: Refer to the ActiveSocket Library and create the objects

Now that a new project has been created, you must add a reference to the ActiveSocket Toolkit in the project to be able to use the the ActiveSocket 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 'ActiveSocket 3.1 Type Library' as shown in the following picture:

(Click on the picture to enlarge)

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

On top of your code, type the following line to use the ActiveSocket namespace:

Imports ASOCKETLib

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

Public m_objSocket As Tcp

m_objSocket = New Tcp()

Step 4: Establish a TCP/IP connection to a remote server

You can now use the Socket object to establish a TCP/IP connection to a remote server..

The following code shows how to write a simple Telnet application in Visual Basic.NET:

Imports ASOCKETLib

Public Class TelnetGuiApp
    Inherits System.Windows.Forms.Form

    Public m_Socket As Tcp

#Region " Windows Form Designer generated code "
#End Region

    Private Sub TelnetGuiApp_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        m_Socket = New Tcp()
        m_Socket.Protocol = m_Socket.asPROTOCOL_TELNET   ' Telnet instead of RAW
    End Sub

    Private Sub BTN_CONNECT_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTN_CONNECT.Click
        m_Socket.Connect(TXT_HOST.Text, 23)
        TXT_RESULT.Text = m_Socket.LastError.ToString() & " (" & m_Socket.GetErrorDescription(m_Socket.LastError) & ")"
    End Sub

    Private Sub BTN_SEND_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTN_SEND.Click
        m_Socket.SendString(TXT_COMMAND.Text)
        TXT_RESULT.Text = m_Socket.LastError.ToString() & " (" & m_Socket.GetErrorDescription(m_Socket.LastError) & ")"
    End Sub

    Private Sub BTN_CLOSE_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTN_CLOSE.Click
        Close()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

        If (m_Socket.ConnectionState = m_Socket.asCONN_CONNECTED) Then
            TXT_RECEIVED.Text += m_Socket.ReceiveString()

            BTN_DISCONNECT.Enabled = True
            BTN_SEND.Enabled = True
            TXT_RECEIVED.Enabled = True
            TXT_COMMAND.Enabled = True
        Else
            TXT_RECEIVED.Text = ""

            BTN_DISCONNECT.Enabled = True
            BTN_SEND.Enabled = False
            TXT_RECEIVED.Enabled = False
            TXT_COMMAND.Enabled = False
        End If
    End Sub

    Private Sub BTN_DISCONNECT_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTN_DISCONNECT.Click
        m_Socket.Disconnect()
        TXT_RESULT.Text = m_Socket.LastError.ToString() & " (" & m_Socket.GetErrorDescription(m_Socket.LastError) & ")"
    End Sub

    Private Sub TXT_URLCOMP_LinkClicked_1(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles TXT_URLCOMP.LinkClicked
        System.Diagnostics.Process.Start("http://www.activexperts.com/files/network-component/asocket.dll")
    End Sub

    Private Sub TXT_URLMANUAL_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles TXT_URLMANUAL.LinkClicked
        System.Diagnostics.Process.Start("http://www.activexperts.com/files/network-component/manual.htm")
    End Sub
End Class

There are many working samples included with the product. You can also find them on the ActiveXperts FTP site: ftp.activexperts-labs.com/samples/network-component.

NOTE: Demo Projects are created with Microsoft Visual Studio 2002

The the ActiveSocket project ships with a set of Microsoft Visual Studio .NET samples, including samples for Microsoft Visual Basic .NET. The projects are created with Microsoft Visual Studio 2002. Users with a later version of Microsoft Visual Studio can open such a project. The Visual Studio Conversion Wizard will guide you through the process of converting the project to the version used.

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