[FENIXadr]

Bueno gente... si ya han viasto los links del post anterior, verán que la cosa no está tan regalada... lo que si, está muuuy interesante..

del Primer link podemos sacar muchisima info sobre nuestras tarjetas de red..
yo hice una Unit con lo más importante para mi caso... pero en la primer link del post anterior tienen toda la unit completa..

pero vamos por paso..

primero hacemos un proyecto nuevo y le ponemos un TMemo o lo que ustedes quieran para mostrar la IP. (yo deje el TMemo del proyecto que estaba haciendo, pero con un TLabel ya nos es suficiente.)
Despues ejecutamos el programa y nos conectamos y desconectamos a internet para ver como funciona...

Unit1

Código Delphi [-]

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, IDStack, StdCtrls, Registry, WinSock, RegMonitorThread, uAdapterInfo;


type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    procedure WMREGCHANGE(var Msg : TMessage); message WM_REGCHANGE;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  RegMonitorThread : TRegMonitorThread;
  Conectado : Boolean;
  AdapterData: TAdapterInfo;

implementation

{$R *.dfm}

Function GetIP : String;
var i : Integer;
begin
  Result := '0.0.0.0';
  Conectado := False;
  if Get_EthernetAdapterDetail(AdapterData) then
  begin
    for i := 0 to Length(AdapterData) - 1 do
    begin
      if (AdapterData[i].dwType = 23) or (AdapterData[i].dwType = 28) then
      begin
        Result := AdapterData[i].sIpAddress;
        Conectado := True;
      end;
    end;
  end;
end;



procedure TForm1.FormCreate(Sender: TObject);
begin

  RegMonitorThread := TRegMonitorThread.Create;
  with RegMonitorThread do
  begin
    FreeOnTerminate:=True;
    Wnd := Form1.Handle;
    Key := '\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces';
    RootKey := HKEY_LOCAL_MACHINE;
    WatchSub := True;
    Resume;
  end;

  Memo1.Clear;
  Memo1.Lines.Add(GetIP);

end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  RegMonitorThread.Terminate;
end;



procedure TForm1.WMREGCHANGE(var Msg: TMessage);
begin
  Memo1.Clear;
  Memo1.Lines.Add(GetIP);
end;


end.

y aqui tenemos la otra Unit...

Código Delphi [-]


unit uAdapterInfo;

interface

uses
  Winsock, // Para definir "in_addr"
  Classes,
  SysUtils;


const
  MAX_INTERFACE_NAME_LEN = $100;
  ERROR_SUCCESS   = 0;
  MAXLEN_IFDESCR  = $100;
  MAXLEN_PHYSADDR = 8;

  MIB_IF_OPER_STATUS_NON_OPERATIONAL = 0;
  MIB_IF_OPER_STATUS_UNREACHABLE = 1;
  MIB_IF_OPER_STATUS_DISCONNECTED = 2;
  MIB_IF_OPER_STATUS_CONNECTING  = 3;
  MIB_IF_OPER_STATUS_CONNECTED   = 4;
  MIB_IF_OPER_STATUS_OPERATIONAL = 5;

  MIB_IF_TYPE_OTHER    = 1;
  MIB_IF_TYPE_ETHERNET = 6;
  MIB_IF_TYPE_TOKENRING = 9;
  MIB_IF_TYPE_FDDI     = 15;
  MIB_IF_TYPE_PPP      = 23;
  MIB_IF_TYPE_LOOPBACK = 24;
  MIB_IF_TYPE_SLIP     = 28;

  MIB_IF_ADMIN_STATUS_UP      = 1;
  MIB_IF_ADMIN_STATUS_DOWN    = 2;
  MIB_IF_ADMIN_STATUS_TESTING = 3;

  _MAX_ROWS_ = 20;
  ANY_SIZE   = 1;


type
  MIB_IFROW = record
    wszName:    array[0 .. (MAX_INTERFACE_NAME_LEN * 2 - 1)] of char;
    dwIndex:    longint;
    dwType:     longint;
    dwMtu:      longint;
    dwSpeed:    longint;
    dwPhysAddrLen: longint;
    bPhysAddr:  array[0 .. (MAXLEN_PHYSADDR - 1)] of byte;
    dwAdminStatus: longint;
    dwOperStatus: longint;
    dwLastChange: longint;
    dwInOctets: longint;
    dwInUcastPkts: longint;
    dwInNUcastPkts: longint;
    dwInDiscards: longint;
    dwInErrors: longint;
    dwInUnknownProtos: longint;
    dwOutOctets: longint;
    dwOutUcastPkts: longint;
    dwOutNUcastPkts: longint;
    dwOutDiscards: longint;
    dwOutErrors: longint;
    dwOutQLen:  longint;
    dwDescrLen: longint;
    bDescr:     array[0 .. (MAXLEN_IFDESCR - 1)] of char;
  end;

type
  MIB_IPADDRROW = record
    dwAddr:      longint;
    dwIndex:     longint;
    dwMask:      longint;
    dwBCastAddr: longint;
    dwReasmSize: longint;
    unused1:     word;
    unused2:     word;
  end;


type
  _IfTable = record
    nRows: longint;
    ifRow: array[1.._MAX_ROWS_] of MIB_IFROW;
  end;

type
  _IpAddrTable = record
    dwNumEntries: longint;
    table: array[1..ANY_SIZE] of MIB_IPADDRROW;
  end;


type
  TAdapterInfo = array of record
    dwIndex:    longint;
    dwType:     longint;
    dwMtu:      longint;
    dwSpeed:    extended;
    dwPhysAddrLen: longint;
    bPhysAddr:  string;
    dwAdminStatus: longint;
    dwOperStatus: longint;
    dwLastChange: longint;
    dwInOctets: longint;
    dwInUcastPkts: longint;
    dwInNUcastPkts: longint;
    dwInDiscards: longint;
    dwInErrors: longint;
    dwInUnknownProtos: longint;
    dwOutOctets: longint;
    dwOutUcastPkts: longint;
    dwOutNUcastPkts: longint;
    dwOutDiscards: longint;
    dwOutErrors: longint;
    dwOutQLen:  longint;
    dwDescrLen: longint;
    bDescr:     string;
    sIpAddress: string;
    sIpMask:    string;
  end;


function GetIfTable(pIfTable: Pointer; var pdwSize: longint; bOrder: longint): longint;
  stdcall;
function GetIpAddrTable(pIpAddrTable: Pointer; var pdwSize: longint;
  bOrder: longint): longint; stdcall;

function Get_EthernetAdapterDetail(var AdapterDataFound: TAdapterInfo): boolean;

implementation

function GetIfTable; stdcall; external 'IPHLPAPI.DLL';
function GetIpAddrTable; stdcall; external 'IPHLPAPI.DLL';

function Get_EthernetAdapterDetail(var AdapterDataFound: TAdapterInfo): boolean;
var
  pIfTable: ^_IfTable;
  pIpTable: ^_IpAddrTable;
  ifTableSize, ipTableSize: longint;
  tmp:      string;
  i, j, k, m: integer;
  ErrCode:  longint;
  sAddr, sMask: in_addr;
  IPAddresses, IPMasks: TStringList;
  sIPAddressLine, sIPMaskLine: string;
  bResult:  boolean;
begin
  bResult  := True; //default return value
  pIfTable := nil;
  pIpTable := nil;

  IPAddresses := TStringList.Create;
  IPMasks     := TStringList.Create;

  try
    // First: just get the buffer size.
    // TableSize returns the size needed.
    ifTableSize := 0; // Set to zero so the GetIfTabel function
    // won't try to fill the buffer yet,
    // but only return the actual size it needs.
    GetIfTable(pIfTable, ifTableSize, 1);
    if (ifTableSize < SizeOf(MIB_IFROW) + Sizeof(longint)) then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // less than 1 table entry?!
    end;

    ipTableSize := 0;
    GetIpAddrTable(pIpTable, ipTableSize, 1);
    if (ipTableSize < SizeOf(MIB_IPADDRROW) + Sizeof(longint)) then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // less than 1 table entry?!
    end;

    // Second:
    // allocate memory for the buffer and retrieve the
    // entire table.
    GetMem(pIfTable, ifTableSize);
    ErrCode := GetIfTable(pIfTable, ifTableSize, 1);

    if ErrCode <> ERROR_SUCCESS then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // OK, that did not work.
      // Not enough memory i guess.
    end;

    GetMem(pIpTable, ipTableSize);
    ErrCode := GetIpAddrTable(pIpTable, ipTableSize, 1);

    if ErrCode <> ERROR_SUCCESS then
    begin
      bResult := False;
      Result  := bResult;
      Exit;
    end;

    for k := 1 to pIpTable^.dwNumEntries do
    begin
      sAddr.S_addr := pIpTable^.table[k].dwAddr;
      sMask.S_addr := pIpTable^.table[k].dwMask;

      sIPAddressLine := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
        '=' + Format('%s', [inet_ntoa(sAddr)]);
      sIPMaskLine    := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
        '=' + Format('%s', [inet_ntoa(sMask)]);

      IPAddresses.Add(sIPAddressLine);
      IPMasks.Add(sIPMaskLine);
    end;

    SetLength(AdapterDataFound, pIfTable^.nRows); //initialize the array or records
    for i := 1 to pIfTable^.nRows do
      try
        //if pIfTable^.ifRow[i].dwType=MIB_IF_TYPE_ETHERNET then
        //begin
        m := i - 1;
        AdapterDataFound[m].dwIndex := 4;//(pIfTable^.ifRow[i].dwIndex);
        AdapterDataFound[m].dwType := (pIfTable^.ifRow[i].dwType);
        AdapterDataFound[m].dwIndex := (pIfTable^.ifRow[i].dwIndex);
        AdapterDataFound[m].sIpAddress :=
          IPAddresses.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
        AdapterDataFound[m].sIpMask :=
          IPMasks.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
        AdapterDataFound[m].dwMtu := (pIfTable^.ifRow[i].dwMtu);
        AdapterDataFound[m].dwSpeed := (pIfTable^.ifRow[i].dwSpeed);
        AdapterDataFound[m].dwAdminStatus := (pIfTable^.ifRow[i].dwAdminStatus);
        AdapterDataFound[m].dwOperStatus := (pIfTable^.ifRow[i].dwOperStatus);
        AdapterDataFound[m].dwInUcastPkts := (pIfTable^.ifRow[i].dwInUcastPkts);
        AdapterDataFound[m].dwInNUcastPkts := (pIfTable^.ifRow[i].dwInNUcastPkts);
        AdapterDataFound[m].dwInDiscards := (pIfTable^.ifRow[i].dwInDiscards);
        AdapterDataFound[m].dwInErrors := (pIfTable^.ifRow[i].dwInErrors);
        AdapterDataFound[m].dwInUnknownProtos := (pIfTable^.ifRow[i].dwInUnknownProtos);
        AdapterDataFound[m].dwOutNUcastPkts := (pIfTable^.ifRow[i].dwOutNUcastPkts);
        AdapterDataFound[m].dwOutUcastPkts := (pIfTable^.ifRow[i].dwOutUcastPkts);
        AdapterDataFound[m].dwOutDiscards := (pIfTable^.ifRow[i].dwOutDiscards);
        AdapterDataFound[m].dwOutErrors := (pIfTable^.ifRow[i].dwOutErrors);
        AdapterDataFound[m].dwOutQLen := (pIfTable^.ifRow[i].dwOutQLen);
        AdapterDataFound[m].bDescr := (pIfTable^.ifRow[i].bDescr);

        tmp := '';
        for j := 0 to pIfTable^.ifRow[i].dwPhysAddrLen - 1 do
        begin
          if Length(tmp) > 0 then
            tmp := tmp + '-' + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]])
          else
            tmp := tmp + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]]);
        end;

        if Length(tmp) > 0 then
        begin
          AdapterDataFound[m].bPhysAddr := tmp;
        end;
      except
        bResult := False;
        Result  := bResult;
        Exit;
      end;
  finally
    if Assigned(pIfTable) then
    begin
      FreeMem(pIfTable, ifTableSize);
    end;

    FreeAndNil(IPMasks);
    FreeAndNil(IPAddresses);
  end;

  Result := bResult;
end;


end.

y listo... aqui tenemos un evento que se dispara cuando nos conectamos o desconectamos...

si pueden comenten...

Saludos ..