Função para verificar se a internet está conectada.

Função para verificar se a internet está conectada.

// function IsConnectedToInternet(): Boolean;

function IsConnectedToInternet(): Boolean;
const
  WininetDLL = 'wininet.dll';
  INTERNET_CONNECTION_MODEM = 1;
  INTERNET_CONNECTION_LAN = 2;
  INTERNET_CONNECTION_PROXY = 4;
  INTERNET_CONNECTION_MODEM_BUSY = 8;
var
  hWininetDLL: THandle;
  dwReserved: DWORD;
  fn_InternetGetConnectedState:
  function(lpdwFlags: LPDWORD; dwReserved: DWORD): BOOL; stdcall;
  dwConnectionTypes: DWORD;
begin
  Result := False;
  dwReserved := 0;
  hWininetDLL := LoadLibrary(WininetDLL);

  if (hWininetDLL > 0) then
  begin
    @fn_InternetGetConnectedState :=
    GetProcAddress(hWininetDLL, 'InternetGetConnectedState');

    if Assigned(fn_InternetGetConnectedState) then
    begin
      Result := fn_InternetGetConnectedState(@dwConnectionTypes,
      dwReserved);
    end;

    FreeLibrary(hWininetDLL);
  end else
    raise Exception.Create(
    'Unable to locate function InternetGetConnectedState in library.'
    + WininetDLL);

end;

// Exemplo de uso
procedure TForm1.Button1Click(Sender: TObject);
begin
  if IsConnectedToInternet then
    ShowMessage('Conectado.')
  else
    ShowMessage('Não Conectado.');
end;