Visual Basic .NET Telnet Sample Source Code

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

Network Component 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.

Network Component can be well integrated into any development platform that supports ActiveX objects.

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Step 1: Download and install the Network Component

Download Network Component 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 2008') 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):

Step 3: Refer to the Network Component Library and create the objects

Now that a new project has been created, you must add a reference to the Network Component in the project to be able to use the the Network 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 'Network Component 4.4 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 Network Component namespace:

Imports AxNetwork

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

Public m_objTcp As Tcp
m_objTcp = New Tcp()

Appendix: Full source code

Imports System.IO
Imports AxNetwork

Module TelnetProgram

    Sub Main()
        Dim objTcp As AxNetwork.Tcp = New AxNetwork.Tcp
        Dim objConstants As AxNetwork.NwConstants = New AxNetwork.NwConstants
        Dim strHost As String = "www.activexperts.com"
        Dim strReceived As String = ""
        Dim numPort As System.Int32 = 80

        ' A license key is required to unlock this component after the trial period has expired.
        ' Call 'Activate' with a valid license key as its first parameter. Second parameter determines whether to save the license key permanently 
        ' to the registry (True, so you need to call Activate only once), or not to store the key permanently (False, so you need to call Activate
        ' every time the component is created). For details, see manual, chapter "Product Activation".
        '
        ' objTcp.Activate("XXXXX-XXXXX-XXXXX", False)

        ' Display component information
        Console.WriteLine("ActiveXperts Network Component {0}{1}Build: {2}{3}Module: {4}{5}License Status: {6}{7}License Key: {8}{9}", objTcp.Version, Environment.NewLine, objTcp.Build, Environment.NewLine, objTcp.Module, Environment.NewLine, objTcp.LicenseStatus, Environment.NewLine, objTcp.LicenseKey, Environment.NewLine)

        ' Set Logfile (optional, for debugging purposes)
        objTcp.LogFile = Path.GetTempPath() + "Tcp.log"
        Console.WriteLine("Log file used: {0}{1}", objTcp.LogFile, Environment.NewLine)

        objTcp.Protocol = objConstants.nwSOCKET_PROTOCOL_TELNET

        ' To enable logging,assign a valid log file to the LogFile property
        ' objTcp.LogFile = "C:\TelnetDemo.log"

        ' Make a connection to remote server
        objTcp.Connect(strHost, numPort)
        Console.WriteLine("Connect( " & strHost & ", " & numPort.ToString() & " ), result: " & objTcp.LastError.ToString() & " (" & objTcp.GetErrorDescription(objTcp.LastError) & ")")

        If (objTcp.LastError = 0 And objTcp.ConnectionState = objConstants.nwSOCKET_CONNSTATE_CONNECTED) Then

            ' YES, connection established.
            Console.WriteLine("Connection established")

            objTcp.Sleep(1000)

            objTcp.SendString("GET /network-component/demopage/ HTTP/1.1")
            objTcp.SendString("Host: www.activexperts.com")
            objTcp.SendString("")

            objTcp.Sleep(1000)

            If (objTcp.HasData()) Then

                strReceived = objTcp.ReceiveString()
                Console.WriteLine("RECV: " + strReceived)
            End If
            objTcp.Sleep(1000)
        End If

        ' And finally, disconnect
        objTcp.Disconnect()
        Console.WriteLine("Disconnect, result: " + objTcp.LastError.ToString() + " (" + objTcp.GetErrorDescription(objTcp.LastError) + ")")

        Console.WriteLine("Ready.")
        System.Threading.Thread.Sleep(5000) ' Sleep for 5 seconds before exit		

    End Sub

End Module

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You can download the complete samples here. There are many other working Network Component scripts on our site and shipped with the product.

NOTE: Demo Projects are created with Microsoft Visual Studio 2008

The Network Component project ships with a set of Microsoft Visual Studio .NET samples, including samples for Microsoft Visual C# .NET. The projects are created with Microsoft Visual Studio 2008.

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.