neb:Bung: If they're.sliding doors can however you're locking them be defeated just by lifting them up and jumping the rollers off the track?That would have been my response as well, you're probably never going to get a high-security solution if what you're going to secure is a wardrobe. Another option if the tracks is exposed is to drop a piece of timber into it and secure it into place with a patio bolt, or bolts at both ends. When you're there, take it out and put it in the wardrobe so there's no sign of it.
If the sliding doors were secured with patio bolts at the bottom of the doors (corners) you could never get the door out. You may get it out of the track but the patio bolt will stop it going any further...