c# - Properties vs. Fields: Need help grasping the uses of Properties over Fields

Question

First off, I have read through a list of postings on this topic and I don't feel I have grasped properties because of what I had come to understand about encapsulation and field modifiers (private, public..ect).

One of the main aspects of C# that I have come to learn is the importance of data protection within your code by the use of encapsulation. I 'thought' I understood that to be because of the ability of the use of the modifiers (private, public, internal, protected). However, after learning about properties I am sort of torn in understanding not only properties uses, but the overall importance/ability of data protection (what I understood as encapsulation) within C#.

To be more specific, everything I have read when I got to properties in C# is that you should try to use them in place of fields when you can because of:

1) they allow you to change the data type when you can't when directly accessing the field directly.

2) they add a level of protection to data access

However, from what I 'thought' I had come to know about the use of field modifiers did #2, it seemed to me that properties just generated additional code unless you had some reason to change the type (#1) - because you are (more or less) creating hidden methods to access fields as opposed to directly.

Then there is the whole modifiers being able to be added to Properties which further complicates my understanding for the need of properties to access data.

I have read a number of chapters from different writers on "properties" and none have really explained a good understanding of properties vs. fields vs. encapsulation (and good programming methods).

Can someone explain:

1) why I would want to use properties instead of fields (especially when it appears I am just adding additional code

2) any tips on recognizing the use of properties and not seeing them as simply methods (with the exception of the get;set being apparent) when tracing other peoples code?

3) Any general rules of thumb when it comes to good programming methods in relation to when to use what?

Thanks and sorry for the long post - I didn't want to just ask a question that has been asked 100x without explaining why I am asking it again.

question from:https://stackoverflow.com/questions/3069901/properties-vs-fields-need-help-grasping-the-uses-of-properties-over-fields

Answer 1

You should not worry about the extra code needed for accessing fields via properties, it will be "optimized" away by the JIT compiler (by inlining the code). Except when it is too large to be inlined, but then you needed the extra code anyway.

And the extra code for defining simple properties is also minimal:

public int MyProp { get; set; } // use auto generated field.

When you need to customize you can alway define your own field later.

So you are left with the extra layer of encapsulation / data protection, and that is a good thing.

My rule: expose fields always through properties