Are C# properties actually Methods?

Question

Till now, I was under the impression that Properties & Methods are two different things in C#. But then I did something like below.

and this was an "Eye Opener" to me. I was expecting one property stringProp and one method stringProp but instead I got this.

Why this happened? can someone explain please.

Answer 1

Strictly speaking, properties are not methods, although they are indeed supported by getter and setter methods (also called accessors). When you write code like this (provided you modify the code to remove the compile error mentioned below)

myFoo.stringProp = "bar"; 

The compiler actually generates IL code like this:

ldstr       "bar" callvirt    foo.set_stringProp 

Where set_stringProp is the setter method for that property. In fact, if you so desired, you can invoke these methods directly via reflection.

However, the code sample you posted may look okay in Visual Studio's intellisense, but it will not compile. Try building the project and you will see an error like:

The type 'foo' already contains a definition for 'stringProp'

Answer 2

Yes, the compiler generates a pair of get and set methods for a property, plus a private backing field for an auto-implemented property.

public int Age {get; set;} 

becomes the equivalent of:

private int <Age>k__BackingField;  public int get_Age() {      return <Age>k__BackingField; }  public void set_Age(int age) {     <Age>k__BackingField = age; } 

Code that accesses your property will be compiled to call one of these two methods. This is exactly one of the reasons why changing a public field to be a public property is a breaking change.

See Jon Skeet's Why Properties Matter.