FAQ: Interfaces - What Interfaces Cannot Do

This community-built FAQ covers the “What Interfaces Cannot Do” exercise from the lesson “Interfaces”.

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In the constructor:

this.Wheels = 4;

but the Wheels property has no setter only a getter.

public int Wheels
    { get; }

How is it setting? This should give an error right?

If there is no setter then it can be set in the constructor or through a default value. In other words, when the object is made it can be given a value after than you can’t. So you can’t use initialisation either because it makes the object and then sets the value, like so:

// Not valid
var obj = new WheelsObj() { Wheels = 4 };

Thanks! I think I understand. I looked up object initialisers because they aren’t covered in this course. Can you just write

var obj = new WheelsObj { Wheels = 4 };

without the brackets after WheelsObj? But this is invalid anyway right?

Without the brackets will just call the default constructor before initialisation anyway, so empty brackets and no brackets in object initialisation do the same thing. Which means, yes it still wouldn’t work.

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