C# convention for empty constructor [closed]

Question

I know an empty method without any good reason is a code smell, but it can be required for constructors.

What would be a good way to write an empty constructor among the following?

class A
{
    private int a;
    public A(int v)
    {
         a = v;
    }
}

class B : A
{
     // 1
     public B(int v) : base(v) { }

     // 2
     public B(int v) : base(v)
     { } 

     // 3
     public B(int v) : base(v)
     {
     } 
}

Answer 1

This is how I do it:

    public B(int v)
        : base(v)
    {
        // Empty
    }

Motivation is that I want to be explicit on the fact that I intend this to be an empty code block. When I come back to this code some time in the future, I'd know that it is not that I forgot to write the code.

Consider also to extend the comment with the an explanation of why the code block should not be removed, in particular if removing it does not break the build.

Answer 2

If the class won't be used by third parties and you don't need an overloaded constructor, don't write an empty constructor.

But...

Imagine you already shipped the product, and third parties use your class. A few months later there's a new requirement that makes you add a constructor with an argument.

Now, by doing so, the C# compiler no longer generates a default constructor. If you don't add an empty constructor explicitly, the third party code will be break.

In my opinion, you should always define empty constructors (one liner) for public classes used by third parties.

public B() { }