arduino car with c# simple control

i have a arduino car, the car has a button, when i press that button, the car will follow the black line stick on the ground and go from one side to the other side. The car can run perfectly, but i want to upgrade. Now, i want to add a wifi module to the arduino car, you need to write a c# program, the c# program has a GUI interface, when i press the button on c#, the signal will send from pc to the arduino car through wifi, and the car will move from one side to the other side, just like i press the button on the car. So you need to amended the arduino code i sent you for upgrade the wifi module and write a new c# program to communicate with the arduino car. There should be a field that i can type in the ip address of arduino car as i have 3 arduino cars, you need to make 3 button and 3 ip address field, i want to control 3 arduino car simultaneously.