First check that there isn't anything blocking the drain area inside the bottom of the dishwasher
. Sometimes plastic wrap, a small Tupperware, etc. top gets sucked against the drain and blocks discharge. If nothing is there, (look really good, by getting out as much water as possible!!!). If nothing there, see if you have an "air-break" installed at the kitchen sink
, this prevents backflow from the sink drain back into the dishwasher, check it by removing the decorative cover and see if it is clean and has no obstructions blocking water flow.
Another thing to check, is if you recently had a new disposal installed, it's possible that the dishwasher inlet was never "punched out" to allow for the dishwasher to drain thru the disposal. If none of those, continue with the investigation!
Check to see if some broken glass might have worked its' way into the drain area, beneath the drain discharge guard. You'll have to remove the cover, some are just clipped in place while others have a screw holding them in place.
If still nothing, it is possible that something has worked its' way all the way into the discharge pump section and you'll need to remove the dishwasher from under the counter to get at the pump section.
Normally when the dishwasher is in the pump out sequence, you can hear the pump motor and impeller spinning, if you can't, then proceed with removing the dishwasher and disconnect the power or shut off the breaker to it. It is quite possible that something has jammed the discharge impeller and is preventing pump out. Again, if you can hear the motor and impeller running, it could still have an obstruction. Bucket and towels will be needed to soak up all any water that you couldn't remove before pulling the dishwasher out from under the countertop.
If there is no obstruction in the discharge pump section and the discharge value (usually a simple rubber flap) is moving freely, then it could be the pump out solinoid (an electronic valve that opens the discharge port for pumping out water when the dishwasher is done washing and is signaled to drain. You should be able to cycle the dishwasher through a short cycle (wash & rinse) to see if everything is working OK. You'll need to reconnect the power, water inlet and discharge (drain) lines first to check this option.