Why to use Property and not Variable

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We are mostly suggested to not to use public variables, but to told to use property.
if i can do same thing with public variable, then why to use property?

Posted 12-Apr-11 0:09am

zingoraa

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5 solutions

Solution 3

Check out these articles which can help you to understand why property is needed :

http://dotnetguts.blogspot.com/2007/07/advantage-of-using-properties.html[^]

http://www.devarticles.com/c/a/C-Sharp/Understanding-Properties-in-C-Sharp/[^]

Posted 12-Apr-11 0:29am

Tarun.K.S

Comments

Sergey Alexandrovich Kryukov 12-Apr-11 13:24pm

Sure, a 5.
--SA

Tarun.K.S 12-Apr-11 14:46pm

Thanks SA!

Solution 4

A property encapsulates a private variable. So the property itself controls
access to the variable and invoke business rules if needed.

Example:
int m_inning ;

If m_inning is public, it could be assigned any valid int value. But what if
you meant m_inning to hold only 1 thru 9?
The following property would enforce that business rule.

public int Inning()
{
set
{
if (value < 1 || value > 9) throw new InvalidArgumentException();
m_inning = value;
}
}

so for me its better to use properties

Posted 12-Apr-11 0:39am

Mahendra.p25

Updated 12-Apr-11 0:40am

v2

Comments

Sergey Alexandrovich Kryukov 12-Apr-11 13:27pm

Well, not only. You should not mix up access with the issue "property vs. field".
Getters and setters is the key (side effect), not access! Failure to explain it makes the Answer misleading.
This: "so for me its better to use properties" make me think you might not understand it well your self. Properties without fields are not possible, you cannot just "prefer" properties.
--SA

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OriginalGriff · Accepted Answer · 2011-04-12T00:17:00

Solution 1

Because if it is a public property, then you can change the internals of your class without affecting the outside world.

For example, if you have a class with a public variable "username" which holds data like "Mr Paul Jones" and "Mrs Alison Mary Smith", it works fine.
Until you realise that your class would work better if you used four name parts instead:

Status title;
string firstName;
string middleNames;
string lastName;

What happens to the outside world? Every class that used yours relies on "username": but it doesn't exist!

If username is a property, you can provide a getter and a setter that makes it work with the internal form, but looks just like the external form to legacy classes - nothing outside needs to change, you just have to test your revised class.

Posted 12-Apr-11 0:17am

OriginalGriff

Comments

zingoraa 12-Apr-11 6:20am

thank you a lot sir.
But still if in luckiest case nothing changes, yet again why property?

OriginalGriff 12-Apr-11 6:33am

How do you know what changes you will need to make next week?
Design it to allow for changes to have the minimum impact. Properties allow you to help with that: if your variables are all private, then the only way they outside world can interact is via the mechanisms you specify. This helps encapsulate you class, and control the impact of changes later. Result: cleaner code, and higher reliability.

zingoraa 12-Apr-11 6:45am

thx sir, i got the answer.

CodingLover 12-Apr-11 8:08am

yes it is. specially with web developments you've to do lots of changes in early stages of the product. and there may be some modifications after the deployment is done.

Sergey Alexandrovich Kryukov 12-Apr-11 13:29pm

Well, can be public, can be internal. Also, the point is side effect of property (getter/setter) not the access (this is not related).
--SA

OriginalGriff 12-Apr-11 14:46pm

Hi SA! On an unrelated subject, there is an edict from On High about what to do with lazy questions: http://www.codeproject.com/Messages/3854264/Re-QA.aspx
Nice to know what the official line is, isn't it?

Sergey Alexandrovich Kryukov 12-Apr-11 14:49pm

I could not be more agree with Chris on that!
You probably know that I am pretty tough on bad Questions (well, you can be too, I appreciate it).
Thank you very much for this link, Griff.
--SA

OriginalGriff 12-Apr-11 14:52pm

Welcome!

CPallini · Accepted Answer · 2011-04-12T00:42:00

Solution 5

Because properties enforces encapsulation that is a fundamental OOP concept: they allow changing the object's behaviour without directly 'touching' the object internals.
:-)

Posted 12-Apr-11 0:42am

CPallini

Comments

Sergey Alexandrovich Kryukov 12-Apr-11 13:24pm

Short and to the point. My 5.
--SA

CPallini 12-Apr-11 13:50pm

Thank you (by the way you gave the perfect definition for the C programming language) :-)

Sergey Alexandrovich Kryukov 12-Apr-11 15:01pm

You look like a fun of this language. I'm not. :-)
--SA

CPallini 12-Apr-11 15:29pm

Yes, I have a great fun with this language (not always, I've to admit. Going with Lua is fantastic when C becomes painful).

Sergey Alexandrovich Kryukov 12-Apr-11 16:25pm

I like learning exotics languages, even marginal. To me, this is a good sign of a potentially good engineer, too.
--SA

CodingLover · Accepted Answer · 2011-04-12T00:23:00

use of public variables and public properties are following OOP concepts and is a generally accepted best practice. My advice is to familiar with them from the beginning.

The are many reasons to advice to use public property over a public variable. If you could search on the web. I feel following two are the most benefited.

1. Scalability. You can easily add code to the property to perform validation and related stuff.

2. Properties provide better status controlling (different versions may be) because of the ease-of scalability.

Why to use Property and not Variable

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