获取电脑的网络状态

//需要引用 Winapi.Windows 和 Winapi.WinInet两个单元
var
  Winapi.Windows,Winapi.WinInet;

//函数实现
function IsNetworkConnected(var AMsg:string): Boolean;
var
  Flags: DWORD;
begin
  AMsg := '';
  Result := False;
  if InternetGetConnectedState(@Flags, 0) then
  begin
    if ((Flags and INTERNET_CONNECTION_MODEM) = INTERNET_CONNECTION_MODEM) then
    begin
      AMsg := '在线(拨号)';
      Result := True;
    end;
    if ((Flags and INTERNET_CONNECTION_LAN) = INTERNET_CONNECTION_LAN) then
    begin
      AMsg := '在线(局域网)';
      Result := True;
    end;
    if ((Flags and INTERNET_CONNECTION_PROXY) = INTERNET_CONNECTION_PROXY) then
    begin
      AMsg := '在线(代理)';
      Result := True;
    end;
  end;
end;

//调用/使用
var
  _NetStates : Boolean;
  _sMsg : string;
begin
  _NetStates := IsNetworkConnected(_sMsg);
end