Visual Basic .NET SNMP 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.

SNMP can be well integrated into ASP .NET (Visual Basic) environments.

This document describes how Network Component's SNMP objects can be integrated into ASP .NET (Visual Basic) projects.

Network Component is compliant with SNMP v1 and SNMP v2c. Different SNMP data types are supported, including:

String types (also called "octet strings");
Integer types (16bit, 32bit, 64bit and unsigned integers);
IP Address types;
Timetick types;
Counter types (32bit and 64bit counters);
OID types (also called "Object ID's");
Other, less frequently used datatypes.

The following operations are supported:

Get - retrieve an object variable from the (remote) agent;
GetNext - retrieve the next object variable from a table or list within an agent;
Set - set values for object variables within an agent.

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):

(Click on the picture to enlarge)

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 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 Network Component namespace:

Imports AxNetwork

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

Public objSnmp As SNMP

objSnmp = New Snmp()

Appendix: Full source code

Imports System.IO
Imports AxNetwork

Module SnmpProgram

    Private g_objConstants As NwConstants

    Sub Main()
        Dim objSnmpManager As AxNetwork.SnmpManager = New AxNetwork.SnmpManager
        Dim objSnmpObject As AxNetwork.SnmpObject
        Dim strHostName As String = ""
        Dim strCommunity As String = ""
        Dim strMibFile As String = ""
        Dim strOID As String = ""

        ' 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".
        '
        ' objSnmpManager.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}", objSnmpManager.Version, Environment.NewLine, objSnmpManager.Build, Environment.NewLine, objSnmpManager.Module, Environment.NewLine, objSnmpManager.LicenseStatus, Environment.NewLine, objSnmpManager.LicenseKey, Environment.NewLine)

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

        g_objConstants = New NwConstants

        strHostName = ReadInput("Enter SNMP (remote) host (leave blank to use 'localhost'):", "localhost")
        strCommunity = ReadInput("Enter community (leave blank to use 'public'):", "public")
        strMibFile = ReadInput("Enter MIB file (optional):", "")
        Console.WriteLine("Agent: " & strHostName)
        Console.WriteLine("Community: " & strCommunity)
        Console.WriteLine("MIB file: " & strMibFile)

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

        ' Set protocol version
        objSnmpManager.ProtocolVersion = g_objConstants.nwSNMP_VERSION_V2C

        ' SNMP Initialize
        objSnmpManager.Initialize()
        Console.WriteLine("Initialize, result: " & objSnmpManager.LastError.ToString() & " (" & objSnmpManager.GetErrorDescription(objSnmpManager.LastError) & ")")
        If (objSnmpManager.LastError <> 0) Then
            System.Threading.Thread.Sleep(5000) ' Sleep for 5 seconds before exit		
            Exit Sub
        End If

        If (strMibFile <> "") Then
            objSnmpManager.LoadMibFile(strMibFile)
        End If


        ' SNMP session. Pass hostname and community. 
        objSnmpManager.Open(strHostName, strCommunity, 161)
        Console.WriteLine("Open, result: " & objSnmpManager.LastError.ToString() & " (" & objSnmpManager.GetErrorDescription(objSnmpManager.LastError) & ")")
        If (objSnmpManager.LastError = 0) Then
            strOID = "system.sysName.0"
            objSnmpObject = objSnmpManager.Get(strOID)
            If (objSnmpManager.LastError <> 0) Then
                Console.WriteLine("Get, result: " & objSnmpManager.LastError.ToString() & " (" & objSnmpManager.GetErrorDescription(objSnmpManager.LastError) & ")")

            Else
                While (objSnmpManager.LastError = 0)

                    PrintSnmpObject(objSnmpObject)
                    objSnmpObject = objSnmpManager.GetNext()
                End While

                objSnmpManager.Close()
                Console.WriteLine("Close, result: " & objSnmpManager.LastError.ToString() & " (" & objSnmpManager.GetErrorDescription(objSnmpManager.LastError) & ")")
            End If
        End If

        objSnmpManager.Shutdown()
        Console.WriteLine("Shutdown, result: " & objSnmpManager.LastError.ToString() & " (" & objSnmpManager.GetErrorDescription(objSnmpManager.LastError) & ")")

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

    Private Function ReadInput(ByVal strTitle As String, ByVal strDefault As String) As String
        Dim strInput As String = ""
        Console.WriteLine(strTitle)
        Console.Write("  > ")
        strInput = Console.ReadLine()
        If (strInput = "") Then
            strInput = strDefault
        End If
        ReadInput = strInput
    End Function

    Private Sub PrintSnmpObject(ByVal objSnmpObject As SnmpObject)
        Console.WriteLine("OID : " + objSnmpObject.OID)
        Console.WriteLine("   Name : " + objSnmpObject.OIDName)
        Console.WriteLine("   Value : " + objSnmpObject.Value)
        Console.WriteLine("   Type  : " + GetTypeString(objSnmpObject.Type))
    End Sub

    Private Function GetTypeString(ByVal numType As Int32) As String
        Dim strType As String = ""

        Select Case numType
            Case g_objConstants.nwSNMP_TYPE_INTEGER32
                GetTypeString = "nwSNMP_TYPE_INTEGER32"
            Case g_objConstants.nwSNMP_TYPE_BITS
                GetTypeString = "nwSNMP_TYPE_BITS"
            Case g_objConstants.nwSNMP_TYPE_OCTETSTRING
                GetTypeString = "nwSNMP_TYPE_OCTETSTRING"
            Case g_objConstants.nwSNMP_TYPE_NULL
                GetTypeString = "nwSNMP_TYPE_NULL"
            Case g_objConstants.nwSNMP_TYPE_OBJECTIDENTIFIER
                GetTypeString = "nwSNMP_TYPE_OBJECTIDENTIFIER"
            Case g_objConstants.nwSNMP_TYPE_SEQUENCE
                GetTypeString = "nwSNMP_TYPE_SEQUENCE"
            Case g_objConstants.nwSNMP_TYPE_IPADDRESS
                GetTypeString = "nwSNMP_TYPE_IPADDRESS"
            Case g_objConstants.nwSNMP_TYPE_COUNTER32
                GetTypeString = "nwSNMP_TYPE_COUNTER32"
            Case g_objConstants.nwSNMP_TYPE_GAUGE32
                GetTypeString = "nwSNMP_TYPE_GAUGE32"
            Case g_objConstants.nwSNMP_TYPE_TIMETICKS
                GetTypeString = "nwSNMP_TYPE_TIMETICKS"
            Case g_objConstants.nwSNMP_TYPE_OPAQUE
                GetTypeString = "nwSNMP_TYPE_OPAQUE"
            Case g_objConstants.nwSNMP_TYPE_COUNTER64
                GetTypeString = "nwSNMP_TYPE_COUNTER64"
            Case g_objConstants.nwSNMP_TYPE_UNSIGNED32
                GetTypeString = "nwSNMP_TYPE_UNSIGNED32"
            Case Else
                GetTypeString = "UNKNOWN"
        End Select
    End Function

End Module

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.