Async sql connectivity

Hi I am using wpf with sql server 2012. As I use sqlconnection.open (); it hangs the window till it the connection get established. So to overcome that i want to use Async programming and want to use sqlconnection.openasync (); so that window become reaponsive to user. Kindly anyone suggest me the best snippet to use the async for sql connectivity... and also have a timout of 30 sec to connect or returns fail if not connected. Thanks