What's the difference between defining a value and using get/set for class constructors?

Question

In an effort to learn a little, I am trying to figure out the difference between defining a value when creating a class and using get; set; I have no idea of the terminology to look up the answer myself. Any help would be greatly appreciated. Are there certain situations you'd use one over the other. I've been using get; set; for a while, but more a matter of habit, not because i understood why.

Example:

public class Post
{
     public Guid guid = new Guid();
     public Guid userguid { get; set; } 
}

There is a more essential difference: `guid` is a **field**, while `userguid` is a **property**. — Sergey Vyacheslavovich Brunov, Jan 18 '14 at 19:16
Please also note, that according to naming guideline, properties usually have Pascal case, i.e. `UserGuid`. More in [naming guideline](http://msdn.microsoft.com/en-us/library/ms229043(v=vs.110).aspx). — antonv, Jan 18 '14 at 19:35

score 4 · Answer 1 · edited May 23 '17 at 12:20

4

{ get; set; } makes auto-implemented property. You can't set default value for that property within it's declaration, so you have to use constructor.

public class Post
{
    public Guid userguid { get; set; }  

    public Post()
    {
        guid = new Guid();
    }
}

You can implement your own, non-auto property with backing field and set the field default value. This way you don't have to implement it within a contructor:

public class Post
{
    private Guid _guid = new Guid();

    public Guid userguid
    {
        get { return _guid; }
        set { _guid = value; }
    }
}

Which way to go? It's really opinion-based.

Couple things to read:

edited May 23 '17 at 12:20

Community

1
1

answered Jan 18 '14 at 19:17

MarcinJuraszek

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Perfect. Thanks for the great explanation. That's exactly what I needed. Appreciate it. – Joopk.com Jan 18 '14 at 20:49
What is the purpose? Can you do something with the get set? – Joopk.com Jan 18 '14 at 20:55

score 2 · Answer 2 · answered Jan 18 '14 at 19:15

The terminology you're looking for is "properties".

public Guid userguid { get; set; }

is equivalent to:

private Guid guid;

public Guid GetGuid() {
   return guid;
}

public Guid SetGuid(Guid value) {
   guid = value;
}

For more info, read: http://msdn.microsoft.com/en-us/library/x9fsa0sw.aspx

What's the difference between defining a value and using get/set for class constructors?

2 Answers2