ActiveXperts Network Component

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Delphi 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 Delphi Project

Launch Borland Delphi from the Start menu. Choose 'New' from the 'File' menu and select your preferred kind of application, for instance: 'VCL Forms Application - Delphi for Win32'. A new Form is displayed in the workspace.

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 Network Component in the project to be able to use the Network Component object. To do so, choose 'Import Component...' from the 'Component' menu. The Import Components' dialog appears. Select 'Import a Type Library':

Borland Delphi

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In the 'Registered Type Libraries' page, select 'Network Component 4.4 Type Library' and click 'Next':

Borland Delphi

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In the 'Components' page, leave all fields default and click 'Next':

Borland Delphi

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In the 'Install' page, select 'Create Unit' and click 'Next':

Borland Delphi

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The interface code is generated now and is shown in the AxNetwork_TLB tab of the project.

Step 4: Declare and create the object

From the Project Manager, open Unit1.bas and add the AxNetwork_TLB to the 'Uses' statement to refer to the Network Component library:

Delphi

(Click on the picture to enlarge)

In the 'private' or 'public' section, declare the following objects:

Appendix: Full source code

{******************************************************************************}
{                                                                              }
{                              ActiveXperts                                    }
{                                                                              }
{                Network Component: Delphi_Console_SNMPdemo                    }
{                                                                              }
{                                                                              }
{                                                                              }
{                                                                              }
{                                                                              }
{                                                                              }
{******************************************************************************}
program SNMPdemo;

{$APPTYPE CONSOLE}

uses
 SysUtils, ActiveX,
 AxNetwork_TLB in '../../Imports/AxNetwork_TLB.pas';

var
 g_objConstants:NwConstants ;

{==============================================================================}
{= G e t   T y p e   S t r i n g ==============================================}
{==============================================================================}
function GetTypeString(numType:integer):string;
var
 strType:string;
begin
 strType := '';

 if( numType = g_objConstants.nwSNMP_TYPE_INTEGER32 )       then strType := 'nwSNMP_TYPE_INTEGER32'	      else
 if( numType = g_objConstants.nwSNMP_TYPE_BITS )            then strType := 'nwSNMP_TYPE_BITS' 			      else
 if( numType = g_objConstants.nwSNMP_TYPE_OCTETSTRING )     then strType := 'nwSNMP_TYPE_OCTETSTRING' 	  else
 if( numType = g_objConstants.nwSNMP_TYPE_NULL )            then strType := 'nwSNMP_TYPE_NULL' 		        else
 if( numType = g_objConstants.nwSNMP_TYPE_OBJECTIDENTIFIER )then strType := 'nwSNMP_TYPE_OBJECTIDENTIFIER'else
 if( numType = g_objConstants.nwSNMP_TYPE_SEQUENCE )        then strType := 'nwSNMP_TYPE_SEQUENCE' 	      else
 if( numType = g_objConstants.nwSNMP_TYPE_IPADDRESS )       then strType := 'nwSNMP_TYPE_IPADDRESS' 		  else
 if( numType = g_objConstants.nwSNMP_TYPE_COUNTER32 )       then strType := 'nwSNMP_TYPE_COUNTER32'       else
 if( numType = g_objConstants.nwSNMP_TYPE_GAUGE32 )         then strType := 'nwSNMP_TYPE_GAUGE32' 		    else
 if( numType = g_objConstants.nwSNMP_TYPE_TIMETICKS )       then strType := 'nwSNMP_TYPE_TIMETICKS' 	    else
 if( numType = g_objConstants.nwSNMP_TYPE_OPAQUE )          then strType := 'nwSNMP_TYPE_OPAQUE'          else
 if( numType = g_objConstants.nwSNMP_TYPE_COUNTER64 )       then strType := 'nwSNMP_TYPE_COUNTER64'       else
 if( numType = g_objConstants.nwSNMP_TYPE_UNSIGNED32 )      then strType := 'nwSNMP_TYPE_UNSIGNED32' 			else
  strType := 'UNKNOWN';

 GetTypeString:= strType;
end;

{==============================================================================}
{= P r i n t   S N M P   o b j e c t ==========================================}
{==============================================================================}
procedure PrintSNMPobject(objSnmpObject:SnmpObject);
begin
 WriteLn('OID : ' + objSnmpObject.OID );
 WriteLn(' Value : ' + objSnmpObject.Value );
 WriteLn(' Type  : ' + GetTypeString( objSnmpObject.Type_ ));
end;

{==============================================================================}
{= R e a d   I n p u t ========================================================}
{==============================================================================}
function ReadInput(strTitle:string;strDefault:string):string;
var
 strInput:string;
begin
 strInput := '';

 writeLn(strTitle);
 Write('  > ');
 ReadLn(strInput);
 if( strInput = '' )then strInput := strDefault;

 readInput:= strInput;
end;

{==============================================================================}
{==============================================================================}
{= T H E   P R O G R A M   I T S E L F ========================================}
{==============================================================================}
{==============================================================================}
var
 objSNMPmanager:SnmpManager;
 objSNMPobject:SnmpObject;
 strMibFile,
 strHostName,
 strCommunity,
 strOID:string;

 vt:OleVariant;

begin
 CoInitialize(nil);

 objSnmpObject := COSnmpObject.Create();
 objSNMPmanager := COSnmpManager.Create();
 g_objConstants := CONwConstants.Create();

 strMibFile:='';
 strHostName:='';
 strCommunity:='';
 strOID:='';

 // A license key is required to unlock this component after the trial period
 // has expired. Assign the LicenseKey property every time a new instance of
 // this component is created (see code below). Alternatively, the LicenseKey
 // property can be set automatically. This requires the license key to be
 // stored in the registry. For details, see manual, chapter
 // "Product Activation".
 {
 objSNMPmanager.LicenseKey = 'XXXXX-XXXXX-XXXXX';
 }

 Writeln('ActiveXperts Network Component ' + objSNMPmanager.Version + sLineBreak +
   'Build: ' + objSNMPmanager.Build + sLineBreak +
   'Module: ' + objSNMPmanager.Module + sLineBreak +
   'License Status: ' + objSNMPmanager.LicenseStatus + sLineBreak +
   'License Key: ' + objSNMPmanager.LicenseKey + sLineBreak);

 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):', '' );
 WriteLn('Agent: ' + strHostName );
 WriteLn('Community: ' + strCommunity );
 WriteLn('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();
 WriteLn('Initialize, result: ' + IntToStr(objSnmpManager.LastError) + ' (' + objSnmpManager.GetErrorDescription(objSnmpManager.LastError) + ')' );
 if( objSnmpManager.LastError <> 0 )then
  begin
   sleep(5000);
// return;
  end;

 if( strMibFile <> '' )then
	objSnmpManager.LoadMibFile( strMibFile );

 // SNMP session. Pass hostname and community.
 objSnmpManager.Open( strHostName, strCommunity, 161 );
 WriteLn('Open, result: ' + IntToStr(objSnmpManager.LastError) + ' (' + objSnmpManager.GetErrorDescription(objSnmpManager.LastError) + ')' );
 if( objSnmpManager.LastError = 0 )then
  begin
	 strOID := 'system.sysName.0';

	 if( objSnmpManager.LastError <> 0 )then
	  WriteLn('Get, result: ' + IntToStr(objSnmpManager.LastError) + ' (' + objSnmpManager.GetErrorDescription(objSnmpManager.LastError) + ')' )
   else
    begin
     while( objSnmpManager.LastError =0 )do
      begin
  		 PrintSnmpObject(objSnmpObject );
       vt:=objSnmpManager.Get( strOID );
       objSnmpObject:= IDispatch ( vt ) as SnmpObject ;
      end;
     end;

     objSnmpManager.Close();
     WriteLn('Close, result: ' + IntToStr(objSnmpManager.LastError) + ' (' + objSnmpManager.GetErrorDescription(objSnmpManager.LastError) + ')' );
    end;

 objSnmpManager.Shutdown();
 WriteLn('Shutdown, result: ' + IntToStr(objSnmpManager.LastError) + ' (' + objSnmpManager.GetErrorDescription(objSnmpManager.LastError) + ')' );

 WriteLn('Ready.');
 sleep(3000);
 writeln('Done. Press  to close this window');readln;
end.

You can download the complete sample on our FTP site ftp.activexperts-labs.com/samples/network-component/. There are many other working Network Component scripts on our site and shipped with the product.