Does an uppercase property auto-create a lowercase private property in C#?

Question

Take this code:

public int Foo {get;set;}

As opposed to this more complete manually written code:

private int x;
public int X 
{
    get { return x; }
    set { x = value; }
}

In the first example, does the compiler automatically create a private foo property?

I am not sure if this convention I have seen of having a lowercase private property masked by a public-facing uppercase one is just that, convention, or if it's actually part of the language/compiler, and you can either write it out or let it be done for you.

Answer 1

Why not just have a look what's going on?

  public class Test {
    // private int myProp;

    public int MyProp {
      get;
      set;
    }
  }

...

  string report = String.Join(Environment.NewLine, typeof(Test)
    .GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
    .Select(field => field.Name));

  Console.Write(report);

And you'll get quite a weird name

<MyProp>k__BackingField

however this strange backing field name ensures that there'll be no name conflict (you can't declare any field, property, method etc. starting with <).

Edit: if you uncomment // private int myProp; line you'll have

myProp
<MyProp>k__BackingField

please, notice that myProp is not a backing field for the MyProp property.

Answer 2

The casing has nothing to do with it.

Writing a property like below

public int x { get; set; }

will always create and use an anonymous private field which it manipulates via get/set.