Question

I am applying validation logic in the constructor and returning if that fails. But, still the instance is created. How can i make sure that if a logic fails, the ctor should not create the instance.

class Car
{
    public readonly int maxSpeed;
    private int currSpeed = 99;
    public Car(int max)
    {
        if (max > 50)
            return;
    }
    public Car()
    {
        maxSpeed = 55;
    }
}

Answer 1

You should throw an exception in the constructor if validation fails.

Various framework classes do that, look at the System.String or System.DateTime constructors for example.