Visual Basic .NET TFTP Client 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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This document describes how the Network Component FtpServer object can be integrated into your projects.

The most important functions of the FtpServer object are:

• Connect - connect to the (remote) FTP server on port 21 or any alternate port;
• Disconnect - to diconnect after a connect call;
• GetCurrentDir - retrieve the current directory;
• ChangeDir - change the current directory;
• CreateDir - create a new directory;
• RenameDir - rename a directory;
• DeleteDir - delete a directory;
• FindFile - find a specific file in the current directory;
• FindFirstFile - iterate over all files in the current directory; find the first file;
• FindNextFile - iterate over all files in the current directory; find the next file;
• RenameFile - rename a file in the current directory;
• DeleteFile - delete a file in the current directory;
• GetFile - get (download) a file, either using binary transfer or ASCII transfer;
• PutFile - put (upload) a file, either using binary transfer or ASCII transfer;

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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

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

Step 4: Create the object

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

Public m_objTftpServer As TftpServer

m_objTftpServer = New TftpServer()

Appendix: Full source code

Imports System.IO
Imports AxNetwork

Module TftpGetProgram

  Sub Main()
    Dim objTftp As New TftpServer()

    Console.WriteLine(("ActiveXperts Network Component " + objTftp.Build & ", Module ") + objTftp.[Module])
    Console.WriteLine("Expiration Date: " + objTftp.LicenseStatus & vbLf)

    ' Set Logfile (optional, for debugging purposes)
    objTftp.LogFile = Path.GetTempPath() & "Tftp.log"
    Console.WriteLine("Log file used: {0}" & vbLf, objTftp.LogFile)

    Dim strHost As String = ReadInput("Enter a host name or IP address", "srv202.activexperts-labs.com", True)
    Dim strRemoteFile As String = ReadInput("Enter the filename on the remote TFTP host", "/network-component/readme.txt", True)
    Dim strFilename As String = ""

    If strRemoteFile.Contains("/") Then
        strFilename = strRemoteFile.Substring(strRemoteFile.LastIndexOf("/") + 1)
    Else
        strFilename = strRemoteFile
    End If

    Dim strLocalFile As String = ReadInput("Enter the filename on the local machine", String.Format("{0}{1}", Path.GetTempPath(), strFilename), True)

    objTftp.HostPort = 69
    ' Default port for TFTP is 69
    objTftp.[Get](strHost, strRemoteFile, strLocalFile)
    ' objTftp.Put("192.168.31.98", "test.txt", "test.txt");    save to remote server
    Console.WriteLine("Get, result: " & objTftp.LastError.ToString() & " (" & objTftp.GetErrorDescription(objTftp.LastError) & ")")
    Console.WriteLine("Ready.")
    System.Threading.Thread.Sleep(3000)
    ' Sleep for 3 second before exit
  End Sub

  Private Function ReadInput(ByVal strTitle As String, ByVal strDefaultValue As String, ByVal bAllowEmpty As Boolean) As String
    Dim strInput As [String], strReturn As [String] = ""

    If strDefaultValue = "" Then
        Console.WriteLine(strTitle)
    Else
        Console.WriteLine(String.Format("{0}, leave blank to use: {1}", strTitle, strDefaultValue))
    End If

    Do
        Console.Write("  > ")
        strInput = Console.ReadLine()
        If strInput.Length > 0 Then
            strReturn = strInput
        End If
    Loop While strReturn = "" AndAlso Not bAllowEmpty

    If strReturn = "" AndAlso strDefaultValue <> "" Then
        Return strDefaultValue
    End If
    Return strReturn
  End Function

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.