cloud-based antivirus need continues internet connection and i think this is not good idea and also sending my data to antivirus server for scanning is not secure
There will still be permanent cache in you computer storing the latest virus definations. Anyway, when you cannot connect to the internet, the main way of being infected is through thumb drivers, right?And you're not supposing the virus occured one or two years ago which has brcome antique (for viruses) to infect your computer, are you?
And you can choose not to send files to servers automatically or manually submit potential malwares.