What does this mean ? public Name {get; set;}

Question

I see this quiet often in C# documentation. But what does it do?

public class Car
{
   public Name { get; set; }
}

Can I ask why this has been marked as a duplicate? This was asked in 2009 and the "original" was asked in 2011! — Nathangrad, May 12 '17 at 12:17

score 52 · Accepted Answer · answered Aug 21 '09 at 05:35

52

It is shorthand for:

private string _name;

public string Name
{
    get { return _name; }
    set { _name = value; }
}

The compiler generates the member variable. This is called an automatic property.

answered Aug 21 '09 at 05:35

Bryan Watts

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10

... although the name of the field is actually an "unspeakable" name (e.g. `<>__name`) which is invalid as a C# identifier. This stops you from directly accessing the field from your code. The specification term is "automatically implemented property" but most people do indeed call it an automatic property :) – Jon Skeet Aug 21 '09 at 06:19
6

... But _why_? Why is this _any_ different than `public string Name;`? – Qix - MONICA WAS MISTREATED May 03 '17 at 12:27
@Qix that is the syntax for a field. Properties and fields are semantically distinct; there are reasons to use one or another in various situations. – Bryan Watts May 03 '17 at 15:51
@Bryan, if those reasons and situations build the context to use automatic properties, they should be explained. Unfortunately, that explanation is lacking in all answers here and in other questions. – user1840267 Aug 15 '17 at 09:59
@user1840267: The semantics you describe are of `properties`, a wider category than `automatic properties`, and out of scope for a question asking what they are, not how to use them. – Bryan Watts Aug 15 '17 at 21:25
1

@Brian: Ok, sorry. My point is the one Qix asked: After reading all the answers and comments, I still don't understand the advantage of the automatic property syntax vs. a simple declaration. I was hoping that some reasons and explanations would clarify that. – user1840267 Oct 12 '17 at 11:40
@user1840267: Less code, less potential for human error, less how and more why. Essentially the same reasons as other syntactic sugar. – Bryan Watts Oct 12 '17 at 15:29

score 36 · Answer 2 · answered Jan 15 '12 at 19:50

In simple terms they are referred as property accessors. Their implementation can be explained as below

1.get{ return name} The code block in the get accessor is executed when the property is Read.

2.set{name = value} The code block in the set accessor is executed when the property is Assigned a new value.

Eg.(Assuming you are using C#)

 class Person
 {
     private string name;  // the name field
     public string Name    // the Name property
     {
         get
         {
             return name;
         }
         set
         {
             name = value;
         }
     }
 }

Now when you refer to this property as below
Person p = new Person();// Instantiating the class or creating object 'p' of class 'Person'
```
System.Console.Write(p.Name);  //The get accessor is invoked here
```

The get accessor is invoked to Read the value of property i.e the compiler tries to read the value of string 'name'.

2.When you Assign a value(using an argument) to the 'Name' property as below

Person p = new Person();
p.Name = "Stack"  // the set accessor is invoked here
Console.Writeline(p.Name) //invokes the get accessor
Console.ReadKey(); //Holds the output until a key is pressed

The set accessor Assigns the value 'Stack" to the 'Name property i.e 'Stack' is stored in the string 'name'.

Ouput:

Stack

What's the reason for having a get and set in the first place, why not just use one accessor for both setting and getting, this is the question nobody seems capable of answering in simple terms. — JsonStatham, Nov 13 '15 at 17:37
@JsonStatham it's so you can add code to check or modify the value before assignment. for example `set { name = value + "."; }` would a a dot to the string. following that same idea, `get` can modify the value before returning it. — UpTide, Nov 21 '18 at 22:13
Just tell me the proper syntax and I am good. If you make "Name" static but with getter and setter, what is the syntax to access it, from the same class and from a different class? — Baruch Atta, Apr 29 '19 at 12:55

score 10 · Answer 3 · answered Aug 21 '09 at 05:34

10

It's an automatic read-write property. It's a C# 3.0 addition. Something like:

public class Car {
    private string name;
    public string Name { get { return name; } set { name = value; } }
}

except that you can't directly access the backing field.

answered Aug 21 '09 at 05:34

Mehrdad Afshari

414,610
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789

score 4 · Answer 4 · answered Aug 21 '09 at 05:39

It's called an Auto-Implemented Property and is new to C# 3.0. It's a cleaner syntax when your access to the property doesn't need any special behavior or validation. It's similar in function to:

public class Car
{
  private string _name;
  public string Name
  {
    get { return _name; }
    set {_name = value; }
  }
}

So it saves a fair amount of code, but leaves you the option later to modify the accessor logic if behavior or rules need to change.

score 3 · Answer 5 · answered Aug 21 '09 at 05:38

3

It is the equivilent of doing:

private string _Text;

public string Text 
{
    get { return _Text; }
    set { _Text = value; }
}

Except you don't have access to the private variable while inside the class.

answered Aug 21 '09 at 05:38

Darthg8r

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So if you want to keep the private variable you have to use the "old" format (as in your example)? – Rado Mar 08 '15 at 18:18

score 1 · Answer 6 · answered Aug 21 '09 at 05:41

1

Auto-Implemented Properties

SUMMARY:In C# 3.0 and later, auto-implemented properties make property-declaration more concise when no additional logic is required in the property accessors.

answered Aug 21 '09 at 05:41

KV Prajapati

93,659
19
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What does this mean ? public Name {get; set;}

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