Detecção de conexão à internet 2: a missão

If (NMFtp1.GetLocalAddress <> ´0,0,0,0´) Then 
   ShowMessage(´Você não está conectado!´) 
Else 
   ShowMessage(´Você está conectado!´);

unit Unit4;

interface

uses
Windows, SysUtils, Registry, WinSock, WinInet;

type
   TConnectionType = (ctNone, ctProxy, ctDialup);

function ConnectedToInternet : TConnectionType; 
function RasConnectionCount : Integer; 
 
 
implementation 
 
const 
   cERROR_BUFFER_TOO_SMALL = 603;
   cRAS_MaxEntryName = 256;
   cRAS_MaxDeviceName = 128;
   cRAS_MaxDeviceType = 16;
type
   ERasError = class(Exception);

   HRASConn = DWord;
   PRASConn = ^TRASConn;
   TRASConn = record
   dwSize: DWORD;
   rasConn: HRASConn;
   szEntryName: Array[0..cRAS_MaxEntryName] Of Char;
   szDeviceType : Array[0..cRAS_MaxDeviceType] Of Char;
   szDeviceName : Array [0..cRAS_MaxDeviceName] of char;
end;

TRasEnumConnections =

function (RASConn: PrasConn; { buffer para receber dados da conexao}
var BufSize: DWord; { tamanho em bytes do buffer }
var Connections: DWord { numero de conexoes escritas no buffer }
): LongInt; stdcall;


function ConnectedToInternet: TConnectionType;
var
   Reg : TRegistry;
   bUseProxy : Boolean;
   UseProxy : LongWord;
begin
   Result := ctNone;
   Reg := TRegistry.Create;
   with REG do
   try
      try
      RootKey := HKEY_CURRENT_USER;
      if OpenKey(´\Software\Microsoft\Windows\CurrentVersion\Internet settings´,False) then
         begin
         //I just try to read it, and trap an exception
         if GetDataType(´ProxyEnable´) = rdBinary then
            ReadBinaryData(´ProxyEnable´, UseProxy, SizeOf(LongWord) )
         else
            begin
            bUseProxy := ReadBool(´ProxyEnable´);
            if bUseProxy then
               UseProxy := 1
            else
            UseProxy := 0;
            end;
         if (UseProxy <> 0) and ( ReadString(´ProxyServer´) <> ´´ ) then Result := ctProxy;
         end;
      except
      //Nao conectado com proxy
      end;
   finally
      Free;
   end;

   if Result = ctNone then
      begin
      if RasConnectionCount > 0 then
         Result := ctDialup;
      end;
end;

function RasConnectionCount : Integer;
var
   RasDLL : HInst;
   Conns : Array[1..4] of TRasConn;
   RasEnums : TRasEnumConnections;
   BufSize : DWord;
   NumConns : DWord;
   RasResult : Longint;
begin
   Result := 0;

   //Load the RAS DLL
   RasDLL := LoadLibrary(´rasapi32.dll´);
   if RasDLL = 0 then
      exit;

   try
   RasEnums := GetProcAddress(RasDLL,´RasEnumConnectionsA´);
   if @RasEnums = nil then
      raise ERasError.Create(´RasEnumConnectionsA not found in rasapi32.dll´);

   Conns[1].dwSize := Sizeof (Conns[1]);
   BufSize := SizeOf(Conns);

   RasResult := RasEnums(@Conns, BufSize, NumConns);

   If (RasResult = 0) or (Result = cERROR_BUFFER_TOO_SMALL) then
      Result := NumConns;
   finally
   FreeLibrary(RasDLL);
   end;
end;

end.

procedure TForm1.Button1Click(Sender: TObject);
begin
   If (RasConnectionCount = 0) Then
      ShowMessage(´Você não está conectado!´)
   Else
      ShowMessage(´Você está conectado!´);
end;