What is the accessibility of the backing fields of auto-implemented properties?

Question

The backing fields are automatically private - am I right?

class Car
{
    public String Mark { get; set; }
    public String Model { get; set; }
}

Are you asking if the properties with `public` access modifiers are `private`? Or if the class is `private`? Or something else? — eye_am_groot, Oct 30 '18 at 16:35
Properties `Mark` and `Model` are auto-implemented properties and by default they can access private fields. — Llazar, Oct 30 '18 at 16:37
Behind the public Properties do we have fields (string mark and string model) ? Are they private? — Heron, Oct 30 '18 at 16:41

score 3 · Answer 1 · answered Oct 30 '18 at 16:43

Auto-implemented properties:

public String Mark { get; set; }
public String Model { get; set; }

When you declare a auto-implemented as shown in your example, the compiler creates a private, anonymous backing field that can only be accessed through the property's get and set accessors.

private string mark;
private string model;
public String Mark { 
   get
   {
   return mark;
   }
   set
   {
   mark = value;
   }
}
public String Model{ 
   get
   {
   return model;
   }
   set
   {
   model = value;
   }
}

Well, they won't be named `mark` and `model`, but yes, other then that this answer is correct. — Zohar Peled, Nov 12 '18 at 11:05

Olivier Jacot-Descombes · Answer 2 · 2018-10-30T17:03:57.300

In

class Car
{
    public string Mark { get; set; }
    string Model { get; set; }
}

The class Car is internal.
The property Mark is public.
The property Model is private.

The comments seem to indicate that you are asking about the accessibility of the backing fields.

Both properties are Auto-Implemented Properties (C# Programming Guide) having a hidden, non-accessible backing field. The documentation for C# auto-implemented properties says:

When you declare a property [...], the compiler creates a private, anonymous backing field that can only be accessed through the property's get and set accessors.

This is different in VB where the backing field is accessible from within the class: Auto-Implemented Properties (Visual Basic).

Also see: What are the default access modifiers in C#?

What is the accessibility of the backing fields of auto-implemented properties?

2 Answers2