用API测试是否连接网络!

uses Wininet;

{$R *.dfm}

function NetWorkIsConnect(Url:string='http://www.microsoft.com/'): Boolean;
var
  ConTypes : Integer;
begin
    Result := false;
    ConTypes := INTERNET_CONNECTION_MODEM + INTERNET_CONNECTION_LAN + INTERNET_CONNECTION_PROXY;
    if InternetGetConnectedState(@ConTypes, 0) then //ConTypes := $01 + $02 + $04;
      Result := True
    else
    if InternetCheckConnection(PWideChar(Url), 1, 0) then
      Result := True;
end;