The best way to detect whether the network is connected under win platform

[Delphi] A function that checks if a URL is valid

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functionCheckUrl(url: string): boolean;var  hSession, hfile, hRequest: hInternet;  dwindex, dwcodelen: dword;  dwcode: array[1..20] ofchar;  res: pchar;begin  ifpos(‘http://‘, lowercase(url)) = 0 then    url := ‘http://‘+ url;  Result := false;  hSession := InternetOpen(‘InetURL:/1.0‘, INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);  ifassigned(hsession) then  begin    hfile := InternetOpenUrl(hsession, pchar(url), nil, 0, INTERNET_FLAG_RELOAD, 0);    dwIndex := 0;    dwCodeLen := 10;    HttpQueryInfo(hfile, HTTP_QUERY_STATUS_CODE, @dwcode, dwcodeLen, dwIndex);    res := pchar(@dwcode);    result := (res = ‘200‘) or(res = ‘302‘);    ifassigned(hfile) then      InternetCloseHandle(hfile);    InternetCloseHandle(hsession);  end;end;

Http://www.cnblogs.com/chonghai/p/5581402.html

http://bbs.2ccc.com/topic.asp?topicid=514550

The best way to detect whether the network is connected under win platform