It depends on the specific dishwasher model and its features. In most modern dishwashers, opening the dishwasher during a cycle will pause the cycle, but it won't start from the beginning when you close the door again. Instead, it will resume from where it left off. This feature is designed to allow users to add or remove dishes or make adjustments mid-cycle.
However, if the dishwasher is opened for an extended period or if the power is turned off while the door is open, some dishwashers might reset the cycle when the door is closed again. In such cases, you may need to select the desired cycle and options again before starting the dishwasher.
To be sure about how your particular dishwasher functions, it's best to consult the dishwasher's user manual or check the manufacturer's guidelines. Additionally, some high-end dishwashers may have more advanced features, so it's always a good idea to understand the specific functions of your appliance to avoid any unintended consequences.