WiFi Auto-connect description

Wifi auto connect application helps you to connect automatically to open wifi networks. wifi auto connect fills the identification form with your id and submit the form as soon as your device connects to a configured wifi network.
android saves wifi details into WifiConfiguration class. When wifi is ON and SSID, Pass-key details matches with wifi network then android auto connect with the particular wifi network. How to disable that auto-connect feature ? purpose behind asking this question is, I have two configured networks (already saved) and i want to connect wifi on the button click event, but auto connect feature of android connects with the wifi itself.
pccw-HKT auto ConnectWi-Fi , pccw Wi-Fi , pccw Wi-Fi , Wi-Fi!: 1. pccw Wi-Fi auto ConnectPCCW-HKT (pccw Wi-Fi auto connect, 1000) 2. Wi-Fi , pccw-HKT brings you an auto connect function! With simple one-time setup, your device will automatically connect from mobile data to Wi-Fi when pccw Wi-Fi is detected, without logging in Wi-Fi every time, save time and enjoy a high speed surfing experience!Notes: 1. This service is applicable only with pccw Wi-Fi "auto connect" service package subscription. (Please call pccw Consumer CS hotline 1000 for pccw Wi-Fi auto connect subscription). 2 If moving out of Wi-Fi coverage, handsets will auto connect to mobile data.