From:http://blog.csdn.net/handsing/archive/2010/08/02/5782089.aspx

    最近需要在c#下面开发snmp的应用，其实我的需求很简单，就是通过一个oid可以获得一个值。在网上搜索了 一些，发现很多文章都是 你抄袭我我抄袭你，基本上拷贝下来是不能运行的，还有的一些利用系统库，有一些用付费的库。
    在网上搜索了一下，发现有一个库相当的好用，SnmpSharpNet。官方网站为http://www.snmpsharpnet.com/。如果有需 要请到官方网站上去下载开源的二进制文件，其中各个的介绍也相当的全面。在进行开发之前请先导入引用。
     在snmp的语句中有两种语句，snmpget/snmpwalk我觉得这两个是我用的最多的，snmpget就是通过oid进行查找，而 snmpwalk可以返回一个组中的数据。下面两段程序演示了具体怎么使用。
snmpget:源地 址：http://www.snmpsharpnet.com/getexample.html

using System;

using System.Net;

using SnmpSharpNet;



namespace snmpget

{

    class Program

    {

        static void Main(string[] args)

        {

            // SNMP community name

            OctetString community = new OctetString("public");



            // Define agent parameters class

            AgentParameters param = new AgentParameters(community);

            // Set SNMP version to 1 (or 2)

            param.Version = (int)SnmpVersion.Ver1;

            // Construct the agent address object

            // IpAddress class is easy to use here because

            //  it will try to resolve constructor parameter if it doesn't

            //  parse to an IP address

            IpAddress agent = new IpAddress("127.0.0.1");



            // Construct target

            UdpTarget target = new UdpTarget((IPAddress)agent, 161, 2000, 1);



            // Pdu class used for all requests

            Pdu pdu = new Pdu(PduType.Get);

            pdu.VbList.Add("1.3.6.1.2.1.1.1.0"); //sysDescr

            pdu.VbList.Add("1.3.6.1.2.1.1.2.0"); //sysObjectID

            pdu.VbList.Add("1.3.6.1.2.1.1.3.0"); //sysUpTime

            pdu.VbList.Add("1.3.6.1.2.1.1.4.0"); //sysContact

            pdu.VbList.Add("1.3.6.1.2.1.1.5.0"); //sysName



            // Make SNMP request

            SnmpV1Packet result = (SnmpV1Packet)target.Request(pdu, param);



            // If result is null then agent didn't reply or we couldn't parse the reply.

            if (result != null)

            {

                // ErrorStatus other then 0 is an error returned by 

                // the Agent - see SnmpConstants for error definitions

                if (result.Pdu.ErrorStatus != 0)

                {

                    // agent reported an error with the request

                    Console.WriteLine("Error in SNMP reply. Error {0} index {1}", 

                        result.Pdu.ErrorStatus,

                        result.Pdu.ErrorIndex);

                }

                else

                {

                    // Reply variables are returned in the same order as they were added

                    //  to the VbList

                    Console.WriteLine("sysDescr({0}) ({1}): {2}",

                        result.Pdu.VbList[0].Oid.ToString(), SnmpConstants.GetTypeName(result.Pdu.VbList[0].Value.Type),

                        result.Pdu.VbList[0].Value.ToString());

                    Console.WriteLine("sysObjectID({0}) ({1}): {2}",

                        result.Pdu.VbList[1].Oid.ToString(), SnmpConstants.GetTypeName(result.Pdu.VbList[1].Value.Type),

                        result.Pdu.VbList[1].Value.ToString());

                    Console.WriteLine("sysUpTime({0}) ({1}): {2}",

                        result.Pdu.VbList[2].Oid.ToString(), SnmpConstants.GetTypeName(result.Pdu.VbList[2].Value.Type),

                        result.Pdu.VbList[2].Value.ToString());

                    Console.WriteLine("sysContact({0}) ({1}): {2}",

                        result.Pdu.VbList[3].Oid.ToString(), SnmpConstants.GetTypeName(result.Pdu.VbList[3].Value.Type),

                        result.Pdu.VbList[3].Value.ToString());

                    Console.WriteLine("sysName({0}) ({1}): {2}",

                        result.Pdu.VbList[4].Oid.ToString(), SnmpConstants.GetTypeName(result.Pdu.VbList[4].Value.Type),

                        result.Pdu.VbList[4].Value.ToString());

                }

            }

            else

            {

                Console.WriteLine("No response received from SNMP agent.");

            }

            target.Dispose();

        }

    }

snmpwalk：源代码地址：http://www.snmpsharpnet.com/walkexample.html

walk有两种方法实现，具体看源出处

using System;

using System.Net;

using SnmpSharpNet;



namespace sharpwalk

{

    class Program

    {

        static void Main(string[] args)

        {

            // SNMP community name

            OctetString community = new OctetString("public");



            // Define agent parameters class

            AgentParameters param = new AgentParameters(community);

            // Set SNMP version to 2 (GET-BULK only works with SNMP ver 2 and 3)

            param.Version = (int)SnmpVersion.Ver2;

            // Construct the agent address object

            // IpAddress class is easy to use here because

            //  it will try to resolve constructor parameter if it doesn't

            //  parse to an IP address

            IpAddress agent = new IpAddress("127.0.0.1");



            // Construct target

            UdpTarget target = new UdpTarget((IPAddress)agent, 161, 2000, 1);



            // Define Oid that is the root of the MIB

            //  tree you wish to retrieve

            Oid rootOid = new Oid("1.3.6.1.2.1.2.2.1.2"); // ifDescr



            // This Oid represents last Oid returned by

            //  the SNMP agent

            Oid lastOid = (Oid)rootOid.Clone();



            // Pdu class used for all requests

            Pdu pdu = new Pdu(PduType.GetBulk);



            // In this example, set NonRepeaters value to 0

            pdu.NonRepeaters = 0;

            // MaxRepetitions tells the agent how many Oid/Value pairs to return

            // in the response.

            pdu.MaxRepetitions = 5;



            // Loop through results

            while (lastOid != null)

            {

                // When Pdu class is first constructed, RequestId is set to 0

                // and during encoding id will be set to the random value

                // for subsequent requests, id will be set to a value that

                // needs to be incremented to have unique request ids for each

                // packet

                if (pdu.RequestId != 0)

                {

                    pdu.RequestId += 1;

                }

                // Clear Oids from the Pdu class.

                pdu.VbList.Clear();

                // Initialize request PDU with the last retrieved Oid

                pdu.VbList.Add(lastOid);

                // Make SNMP request

                SnmpV2Packet result = (SnmpV2Packet)target.Request(pdu, param);

                // You should catch exceptions in the Request if using in real application.



                // If result is null then agent didn't reply or we couldn't parse the reply.

                if (result != null)

                {

                    // ErrorStatus other then 0 is an error returned by 

                    // the Agent - see SnmpConstants for error definitions

                    if (result.Pdu.ErrorStatus != 0)

                    {

                        // agent reported an error with the request

                        Console.WriteLine("Error in SNMP reply. Error {0} index {1}", 

                            result.Pdu.ErrorStatus,

                            result.Pdu.ErrorIndex);

                        lastOid = null;

                        break;

                    }

                    else

                    {

                        // Walk through returned variable bindings

                        foreach (Vb v in result.Pdu.VbList)

                        {

                            // Check that retrieved Oid is "child" of the root OID

                            if (rootOid.IsRootOf(v.Oid))

                            {

                                Console.WriteLine("{0} ({1}): {2}",

                                    v.Oid.ToString(), 

                                    SnmpConstants.GetTypeName(v.Value.Type), 

                                    v.Value.ToString());

                                lastOid = v.Oid;

                            }

                            else

                            {

                                // we have reached the end of the requested

                                // MIB tree. Set lastOid to null and exit loop

                                lastOid = null;

                            }

                        }

                    }

                }

                else

                {

                    Console.WriteLine("No response received from SNMP agent.");

                }

            }

            target.Dispose();

        }

    }

}



}