All of a sudden, the fabric on my moonroof is coming loose and hanging down. There must be a way to fix this yourself. Any experience out there? THX!

Have used the spray on adhesive(repositionable kind) to replace the headliner in a car my boys are redoing worked really well.

Auto parts stores around here carry a spray for headliners. It holds extremely well, but if you get it anywhere you don't want it, you won't be happy.
Those stores may have other products more suited for your problem.

I just had mine done in the Spring of this year. You can get the headliner fabric from Hancock Fabrics. They also have the spray adhesive...you'll need to get the foam spray The headliner material is $12.99 a yard so take a coupon....on average 2 1/2-3 yards are needed unless you have a Suburban. I took mine to someone who did car stereo installs and they put it in for $100.