Inorder to list all the workstations on a LAN, i have used NetServerEnum() after importing it.
On running the program, it seemed to work fine. The two existing machines were detected correctly.
However, i want the list to be refreshed whenever required (some refresh button). So i detached the wire of the other computer from the switch, rendering only a single computer on the LAN.
Now, when i ran the program, it still lists out the disconnected machine.
How to solve this out?
The code is as follows :
namespace LanIpAddresses
{
class NetApi
{
[DllImport ( "Netapi32.dll", EntryPoint = "NetServerEnum" )]
public static extern Int32 NetServerEnum (
[MarshalAs (UnmanagedType.LPWStr)] String serverName,
Int32 level,
out IntPtr bufferPtr,
UInt32 prefMaxLen,
ref Int32 entriesRead,
ref Int32 totalEntries,
UInt32 serverType,
[MarshalAs (UnmanagedType.LPWStr)] String domain,
IntPtr handle );
[DllImport ( "Netapi32.dll", EntryPoint = "NetApiBufferFree" )]
public static extern UInt32 NetApiBufferFree ( IntPtr buffer );
}
class EnumerateLanMachines
{
public const UInt32 SUCCESS = 0;
public const UInt32 FAIL = 234;
public const UInt32 MAX_PREFERRED_LENGTH = 0xFFFFFFFF;
//public ArrayList machines = new ArrayList ( );
enum ServerTypes : uint
{
WorkStation = 0x00000001,
Server = 0x00000002
}
[StructLayout ( LayoutKind.Sequential, CharSet = CharSet.Auto )]
public struct MachineInfo
{
[MarshalAs ( UnmanagedType.U4 )]
public UInt32 platformId;
[MarshalAs ( UnmanagedType.LPWStr )]
public String serverName;
}
public enum Platform
{
PLATFORM_ID_DOS = 300,
PLATFORM_ID_OS2 = 400,
PLATFORM_ID_NT = 500,
PLATFORM_ID_OSF = 600,
PLATFORM_ID_VMS = 700
}
public void enumerateMachines ( )
{
IntPtr buffer = new IntPtr();
int totalEntries = 0;
int entriesRead = 0;
int result;
result = NetApi.NetServerEnum ( null, 100, out buffer, MAX_PREFERRED_LENGTH, ref entriesRead, ref totalEntries, (uint) ServerTypes.WorkStation, null, IntPtr.Zero );
MachineInfo machineInfo;
if (result != FAIL)
{
Console.WriteLine ( "Succeeded!" );
Console.WriteLine ( entriesRead );
for (int i = 0; i < entriesRead; ++i)
{
machineInfo = (MachineInfo) Marshal.PtrToStructure ( buffer, typeof ( MachineInfo ) );
//machines.Add ( machineInfo );
Console.WriteLine ( machineInfo.serverName );
buffer = (IntPtr) ( (ulong) buffer + (ulong) Marshal.SizeOf ( machineInfo ) );
}
NetApi.NetApiBufferFree ( buffer );
}
}
}
}
namespace LanIpAddresses
{
class Program
{
private static IPHostEntry ipHost;
static ArrayList ipList;
static void Main ( string[ ] args )
{
EnumerateLanMachines enumerate = new EnumerateLanMachines ( );
enumerate.enumerateMachines ( );
/*foreach (EnumerateLanMachines.MachineInfo o in enumerate.machines)
{
Console.WriteLine ( o.platformId + " " + o.serverName );
}*/
Console.ReadLine ( );
}
}
}
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