Is there a difference between readonly and { get; }

Question

Do these statements mean the same thing?

int x { get; }
readonly int x;

Answer 1

In answer to your question: There is a difference between readonly and {get; }:

In int x { get; } (which won't compile as there's no way to set x - I think you needed public int x { get; private set; } ) your code can keep changing x

In readonly int x;, x is initialised either in a constructor or inline and then can never change.

Answer 2

readonly int x; declares a readonly field on a class. This field can only be assigned in a constructor and it's value can't change for the lifetime of the class.

int x { get; } declares a readonly auto-implemented property and is, in this form, invalid (because you'd have no way whatsoever to set the value). A normal readonly property does not guarantee to return the same value every time it is called. The value can change throughout the lifetime of the class. For example:

public int RandomNumber
{
    get { return new Random().Next(100); }
}

This will return a different number everytime you call it. (Yes, this is a terrible abuse of properties).