MacBook + External Monitor Display

Hi, I have a MacBook + External Monitor Display setup. Is there anyway when I connect the external monitor that the screen ONLY shows on my big monitor? Right now, I have sort of a dual-display type thing with my big LCD and MB monitor. I want to get rid of that and just have my 22" as the main monitor (when plugged in).

Any ideas?

I have MBP and use an external display. Sometimes when plugging in or unplugging it goes into external only display. So I tried a few things here's how I got it to work. MBP on and external display on as secondary. Then I closed the MBP to put to sleep. Once it was asleep I opened it then closed it. It woke up and now is closed using the external display as primary. I'm sure there are other ways but that just worked for me.

close it to sleep, then wake it up be using a keyboard or mouse.