With locking your child's bedroom door, you may get to the point that she start crying out loud, probably waking you up anyway.
Have you tried locking doors to areas or rooms you definitely don't want her visiting at night? If that is possible.
Locking your bedroom door will probably bring some knocks at the door, but then, if it comes to this, maybe this would work:
<I just answered similarly to the "Crying it out" request (from Rhonda).>
This is not a method I was comfortable using <letting a 7-mo-old "cry it out">. I liked Dr Sears' advice a lot better. I can't accurately recall Dr Sears' method (my boys are 15, 10 and 7 years old already!). But what I do remember is
1) get your child in bed and turn off the light (not including any night light you might be using)
2) stand at the doorway of the bedroom and wait; what you want to do here is be audible so your child knows you are there (hears you hum quietly or hears the floor boards creak, my best was a quiet tap on the door frame), staying there until your child falls asleep,
3) then repeat each time your child wakes up,
as the number of times of waking up decreases and as he/she falls asleep faster, you stand further back, not at the doorway, yet make some slight noise so he knows you are there. From this point, you spend less and less time at the bedroom door or outside the bedroom door, and, hopefully, less times during the night. Until it is not needed any more.
However, this method worked for me, and is recommended, for children as they get close to 3-yrs-old, which, for a lot of kids, is the "I want to be independent" stage; not for a 7-mo-old.
Good luck to you S..