WIN32API returns only current machine name

I want to collect all list of machines in local network, for that I am trying below code. But it always return me current machine name only. How Can I get all machines ip/name in local network?.

I have tried all SV_101_TYPES, among these some returns empty list and remaining returns only current machine name.

Could anyone guide me, what is wrong?

public class Program
    {
        static void Main(string[] args)
        {
            ArrayList machines = NetApi32.GetServerList(NetApi32.SV_101_TYPES.SV_TYPE_ALL);
        }
    }
    /// <summary>
    /// Summary description for Class1.
    /// </summary>
    ///
    public class NetApi32
    {        
        // constants
        public const uint ERROR_SUCCESS = 0;
        public const uint ERROR_MORE_DATA = 234;
        public enum SV_101_TYPES : uint
        {
            SV_TYPE_WORKSTATION = 0x00000001,
            SV_TYPE_SERVER = 0x00000002,
            SV_TYPE_SQLSERVER = 0x00000004,
            SV_TYPE_DOMAIN_CTRL = 0x00000008,
            SV_TYPE_DOMAIN_BAKCTRL = 0x00000010,
            SV_TYPE_TIME_SOURCE = 0x00000020,
            SV_TYPE_AFP = 0x00000040,
            SV_TYPE_NOVELL = 0x00000080,
            SV_TYPE_DOMAIN_MEMBER = 0x00000100,
            SV_TYPE_PRINTQ_SERVER = 0x00000200,
            SV_TYPE_DIALIN_SERVER = 0x00000400,
            SV_TYPE_XENIX_SERVER = 0x00000800,
            SV_TYPE_SERVER_UNIX = 0x00000800,
            SV_TYPE_NT = 0x00001000,
            SV_TYPE_WFW = 0x00002000,
            SV_TYPE_SERVER_MFPN = 0x00004000,
            SV_TYPE_SERVER_NT = 0x00008000,
            SV_TYPE_POTENTIAL_BROWSER = 0x00010000,
            SV_TYPE_BACKUP_BROWSER = 0x00020000,
            SV_TYPE_MASTER_BROWSER = 0x00040000,
            SV_TYPE_DOMAIN_MASTER = 0x00080000,
            SV_TYPE_SERVER_OSF = 0x00100000,
            SV_TYPE_SERVER_VMS = 0x00200000,
            SV_TYPE_WINDOWS = 0x00400000,
            SV_TYPE_DFS = 0x00800000,
            SV_TYPE_CLUSTER_NT = 0x01000000,
            SV_TYPE_TERMINALSERVER = 0x02000000,
            SV_TYPE_CLUSTER_VS_NT = 0x04000000,
            SV_TYPE_DCE = 0x10000000,
            SV_TYPE_ALTERNATE_XPORT = 0x20000000,
            SV_TYPE_LOCAL_LIST_ONLY = 0x40000000,
            SV_TYPE_DOMAIN_ENUM = 0x80000000,
            SV_TYPE_ALL = 0xFFFFFFFF
        };

        [StructLayout(LayoutKind.Sequential)]
        public struct SERVER_INFO_101
        {
            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.U4)]
            public UInt32 sv101_platform_id;
            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.LPWStr)]
            public string sv101_name;

            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.U4)]
            public UInt32 sv101_version_major;
            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.U4)]
            public UInt32 sv101_version_minor;
            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.U4)]
            public UInt32 sv101_type;
            [MarshalAs(System.Runtime.InteropServices.UnmanagedType.LPWStr)]
            public string sv101_comment;
        };
        public enum PLATFORM_ID
        {
            PLATFORM_ID_DOS = 300,
            PLATFORM_ID_OS2 = 400,
            PLATFORM_ID_NT = 500,
            PLATFORM_ID_OSF = 600,
            PLATFORM_ID_VMS = 700
        }

        [DllImport("netapi32.dll", EntryPoint = "NetServerEnum")]
        public static extern int NetServerEnum([MarshalAs(UnmanagedType.LPWStr)]string servername,
           int level,
           out IntPtr bufptr,
           int prefmaxlen,
           ref int entriesread,
           ref int totalentries,
           SV_101_TYPES servertype,
           [MarshalAs(UnmanagedType.LPWStr)]string domain,
           IntPtr resume_handle);

        [DllImport("netapi32.dll", EntryPoint = "NetApiBufferFree")]
        public static extern int
            NetApiBufferFree(IntPtr buffer);

        [DllImport("Netapi32", CharSet = CharSet.Unicode)]
        private static extern int NetMessageBufferSend(
            string servername,
            string msgname,
            string fromname,
            string buf,
            int buflen);

        public static int NetMessageSend(string serverName, string messageName, string fromName, string strMsgBuffer, int iMsgBufferLen)
        {
            return NetMessageBufferSend(serverName, messageName, fromName, strMsgBuffer, iMsgBufferLen * 2);
        }

        public static ArrayList GetServerList(NetApi32.SV_101_TYPES ServerType)
        {
            int entriesread = 0, totalentries = 0;
            ArrayList alServers = new ArrayList();

            do
            {
                // Buffer to store the available servers
                // Filled by the NetServerEnum function
                IntPtr buf = new IntPtr();

                SERVER_INFO_101 server;
                int ret = NetServerEnum(null, 101, out buf, -1, ref entriesread, ref totalentries, ServerType, null, IntPtr.Zero);

                // if the function returned any data, fill the tree view
                if (ret == ERROR_SUCCESS ||
                    ret == ERROR_MORE_DATA ||
                    entriesread > 0)
                {
                    IntPtr ptr = buf;

                    for (int i = 0; i < entriesread; i++)
                    {
                        // cast pointer to a SERVER_INFO_101 structure
                        server = (SERVER_INFO_101)Marshal.PtrToStructure(ptr, typeof(SERVER_INFO_101));

                        //Cast the pointer to a ulong so this addition will work on 32-bit or 64-bit systems.
                        ptr = (IntPtr)((ulong)ptr + (ulong)Marshal.SizeOf(server));

                        // add the machine name and comment to the arrayList.
                        //You could return the entire structure here if desired
                        alServers.Add(server);
                    }
                }

                // free the buffer
                NetApiBufferFree(buf);

            }
            while
                (
                entriesread < totalentries &&
                entriesread != 0
                );

            return alServers;
        }
    }