Automated property with getter only, can be set, why?

Question

I created an automated property:

public int Foo { get; } 

This is getter only. But when I build a constructor, I can change the value:

Answer 1

Auto property feature was added to the language during C# 3.0 release. It allows you to define a property without any backing field, however you still need to use constructor to initialize these auto properties to non-default value. C# 6.0 introduces a new feature called auto property initializer which allows you to initialize these properties without a constructor like Below:

Previously, a constructor is required if you want to create objects using an auto-property and initialize an auto-property to a non-default value like below:

public class MyClass
{
    public int Foo { get; }

    public Foo(int foo)
    {
        Foo = foo;
    }
}

Now in C# 6.0, the ability to use an initializer with the auto-property means no explicit constructor code is required.

public string Foo { get; } = "SomeString";

public List Genres { get; } = new List { "Comedy", "Drama" };

You can find more information on this here