Only wants to fill

There are two possible reasons for the situation as you describe it: 1. Water-inlet valve The water-inlet valve lets water enter the machine. If this valve is defective, you need to completely replace it. It's usually located behind the lower access panel on the left or right side. It's the device with the main water line (usually copper) from the house, a rubber tube to the dishwasher, and two wires attached to it.
2. Float switch The float switch is a small electrical switch that's located right below the dishwasher "floor." Above the switch, on the inside of the dishwasher, is a plastic cylinder that floats up as water fills the dishwasher. If this switch is defective, or if the plastic float gets caught or trapped in the raised position, the water can't enter the dishwasher. If the float switch is defective, you need to replace it.

If you are mechanically inclined you can repair either of these but if you are not you will have to hire it done. Now that you know it is one of two problems you can tell the repairman ahead of time and get a price on the repair. Then shop around for the best price.