I would like to do something like that:
MainForm:
Car car = new Car(); //create new object Form form2 = new Form(car); //Create new form and pass the car
Create a property in form2
public Car MyCar {get; set;}
and set this property
Car car = new Car(); //create new object Form form2 = new Form(); form2.MyCar=car; form2.ShowDialog(); // get car here again Car car2 =form2.MyCar;