Looking for a short & simple example of getters/setters in C#

Question

I am having trouble understanding the concept of getters and setters in the C# language. In languages like Objective-C, they seem an integral part of the system, but not so much in C# (as far as I can tell). I have read books and articles already, so my question is, to those of you who understand getters & setters in C#, what example would you personally use if you were teaching the concept to a complete beginner (this would include as few lines of code as possible)?

Answer 1

I think a bit of code will help illustrate what setters and getters are:

public class Foo {    private string bar;     public string GetBar()    {        return bar;    }     public void SetBar(string value)    {        bar = value;    } } 

In this example we have a private member of the class that is called bar. The GetBar and SetBar methods do exactly what they are named - one retrieves the bar member, and the other sets its value.

In c# 1.1 + you have properties. The basic functionality is also the same:

public class Foo {     private string bar;      public string Bar     {         get { return bar; }         set { bar = value; }     } } 

The private member bar is not accessible outside the class. However the public "Bar" is, and it has two accessors - get, which just as the example above "GetBar()" returns the private member, and also a set - which corresponds to the SetBar(string value) method in the forementioned example.

Starting with C# 3.0 and above the compiler became optimized to the point where such properties do not need to have the private member as their source. The compiler automatically generates a private member of that type and uses it as a source of a property.

public class Foo {    public string Bar { get; set; } } 

what the code shows is an automatic property that has a private member generated by the compiler. You don't see the private member but it is there. This also introduced a couple of other issues - mainly with access control. In C# 1.1, and 2.0 you could omit the get or set portion of a property:

public class Foo {     private string bar;      public string Bar     {         get{ return bar; }     } } 

Giving you the chance to restrict how other objects interact with the "Bar" property of the Foo class. Starting with C# 3.0 and above - if you chose to use automatic properties you would have to specify the access to the property as follows:

public class Foo {     public string Bar { get; private set; } } 

What that means is that only the class itself can set Bar to some value, however anyone could read the value in Bar.

Answer 2

In C#, Properties represent your Getters and Setters.

Here's an example:

public class PropertyExample {     private int myIntField = 0;      public int MyInt     {         // This is your getter.         // it uses the accessibility of the property (public)         get         {             return myIntField;         }         // this is your setter         // Note: you can specify different accessibility         // for your getter and setter.         protected set         {             // You can put logic into your getters and setters             // since they actually map to functions behind the scenes             if (DoSomeValidation(value))             {                 // The input of the setter is always called "value"                 // and is of the same type as your property definition                 myIntField = value;             }         }     } } 

You would access this property just like a field. For example:

PropertyExample example = new PropertyExample(); example.MyInt = 4; // sets myIntField to 4 Console.WriteLine( example.MyInt ); // prints 4 

A few other things to note:

1. You don't have to specifiy both a getter and a setter, you can omit either one.
2. Properties are just "syntactic sugar" for your traditional getter and setter. The compiler will actually build get_ and set_ functions behind the scenes (in the compiled IL) and map all references to your property to those functions.