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();
}
}
}
}