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

“readonly automatically implemented properties”

First of all I want to clarify that the property like

public string FirstName { get; }

Is known as “readonly automatically implemented properties”

To verify this you can run & check the above code with Visual Studio. If you change the language version from C#6.0 to C#5.0 then compiler will throw the following exception Feature 'readonly automatically implemented properties' is not available in C# 5. Please use language version 6 or greater.

to change C# language version visit here

Now I am coming to your second question

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

Microsoft introduces the “readonly automatically implemented properties” on the logic of read only. As we know that the keyword “readonly” is available from C#1.0. we use “readonly” keyword as modifier on a field and that field can be assigned in 2 ways either at the time of declaration or in a constructor in the same class.

In the same way value of “readonly automatically implemented properties” can be assigned in 2 ways

Way1 (at the time of declaration):

public string FirstName { get; } = "Banketeshvar";

Way2 (in a constructor in the same class)

Person()
{
 FirstName  = "Banketeshvar";
}

Purely ReadOnly Property

If you are looking for purely Readonly property then go for this

public string FullName => "Manish Sharma";

now you cannot assign value of “FullName” propery from constructor. If you try to do that it will throw the following exceptions

“Property or indexer 'Person.FullName' cannot be assigned to -- it is read only”