So i am currently learning about events and delegates and wanted to make some testing. I created a class called car. My idea was that everytime i change the value of its tires i want to invoke the event. This is all only for learning purposes. I get an StackoverflowException and i can not figure out why.

private static void Main(string[] args)
        {
            var Car = new Car { Tire_Value = 100 };
            Car.OnTireChanged  = Tirestatus;
            Car.Tire_Value = 10;
        }

        public class Car
        {
            public event EventHandler OnTireChanged;

            public int Tire_Value
            {
                get
                {
                    return this.Tire_Value;
                }

                set
                {
                    this.Tire_Value = value;
                    this.OnTireChanged?.Invoke(this, EventArgs.Empty);
                }
            }
        }

        private static void Tirestatus(object sender, EventArgs args)
        {
            var car = (Car)sender;
            if (car.Tire_Value < 40) Console.WriteLine("Tire is damaged");
        }

CodePudding user response：

When you are setting Tire_Value to a value, your setter is executed, which attempts to call the setter on Tire_Value again, resulting in an infinite loop, and the eventual stack overflow.

The solution to this problem are private backing fields. You declare a private variable of the same type as the public property, in which you store the value. When implementing your custom getter and setter, you use the private field.

This works:

private int _tireValue;
public int TireValue
{
    get => _tireValue;
    set
    {
        _tireValue = value;
        OnTireChanged?.Invoke(this, EventArgs.Empty);
    }
}

You can read another explanation on a different answer. As mentioned there, you can use an automatic property to avoid private backing fields.