What Are Automatic Properties in C# and What Is Their Purpose

What are Automatic Properties in C# and what is their purpose?

Automatic Properties are used when no additional logic is required in the property accessors.

The declaration would look something like this:

public int SomeProperty { get; set; }

They are just syntactic sugar so you won't need to write the following more lengthy code:

 private int _someField;
 public int SomeProperty 
 {
    get { return _someField;}
    set { _someField = value;}
 }

What's the point of an auto property?

Because it gives you the potential to add encapsulated logic later without changing the metadata of the class.

Using properties is considered a best practice - automatically implemented properties were designed to take away the tediousness of writing properties to encourage developers to adhere to this best practice

automatic properties in C#

You're still creating a private variable - it's just done for you behind the scenes by the compiler. The variable is given an "unspeakable name", ensuring you can't refer to it in source code.

You're still getting all the benefits of properties (you can later change from an automatic property to a "manual" property, with no compatibility issues) but without all the cruft. The benefit is just that the code ends up being a lot more concise. I regard that as a significant benefit though :)

C# 3.0 auto-properties — useful or not?

We use them all the time in Stack Overflow.

You may also be interested in a discussion of Properties vs. Public Variables. IMHO that's really what this is a reaction to, and for that purpose, it's great.

what is the exact use of auto implemented properties

Having a field inside a class is not a good idea. using properties allows you to encapsulate your data better. and when you just want to have a field accessible without any logic in you class then you can use automatic properties.

there are many scenarios that using a field inside your class makes things go wrong and harder as your software evolve.

for example: assume you have

public class C
{
    public int Value;
}

in your code base.

then suddenly you realize that Value can not be set to zero. Then you have to make Value private and provide a SetValue() and GetValue() method. This is easy. but wait, how you gonna handle all other codes that relies on Value now?

but think about this one

public class C
{
    public int Value { get; set; }
}

now it just needs a backing field like _value and implementing the setter and getter.

Public Fields versus Automatic Properties

In a related question I had some time ago, there was a link to a posting on Jeff's blog, explaining some differences.

Properties vs. Public Variables

• Reflection works differently on variables vs. properties, so if you rely on reflection, it's easier to use all properties.
• You can't databind against a variable.

• Changing a variable to a property is a breaking change. For example:

  TryGetTitle(out book.Title); // requires a variable
  

Difference between Automatic Properties and public field in C# 3.0

Because they are implemented differently in the resulting IL code (and machine language). An Automatic property is still exposed as a public getter and setter, whereas a public field is just that - a single field..

Thus, implementing an auto property allows you at some later date to change the internal behavior of either the getter or setter (like adding a validator) without recompiling or re=coding any dependant classes that use it...

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