How do I make a grid/tile-based game?

I want to know how to make a grid/tile-based game. Say you are making a game where you can drag and drop sprites on to the screen and you can make a scene of some sort, like a city, but you don't want it to be able to placed just anywhere, only on the grid. How would I do that?

For drag and drop, you have a built in behavior.

About gris, just set the position every tick or at a trigger to round(yourposition*32)/32

32 can be replaced by your grid size

(please note that i wrote that from my memory, the code may not work, tell me if this is the case, i will check later )

Yeah, it doesn't work. Unless I'm doing the trigger wrong though. I scratched the idea of the drag and drop city building game for one where you click and it makes the building if that has anything to do with it.

RexBoard & SquareTx or HexTx

Please see this capx for a demonstration using a tilemap.

https://dl.dropboxusercontent.com/u/706 ... ample.capx

I'm not talking about tilemaps. I'm talking about a Simcity-like game, but you are restricted to putting buildings on a grid.