Lazy loaded property readability

Question

I currently have code that looks like this

private string _stringField;

protected string StringField
{
    get
    {
        if (_stringField == null)
            _stringField = GetStringField();
        return _stringField;
    }
}

ReSharper is suggesting I change the property to:

protected string StringField
{
    get
    {
        return _stringField ?? (_stringField = GetStringField());
    }
}

This isn't an idiom I've seen before and probably would have to think about the first time I saw it; is this something I should be concerned would confuse other people too?

Answer 1

?? is well known operator in C#. It doesn't confuse but reduce coding.

Both snippets have same meaning.

But if it is .NET 4.0 onwards, i would rather use Lazy<T>.

private Lazy<string> lazyStringField = new Lazy<string>(GetStringField);
protected string StringField
{
    get
    {
        return lazyStringField.Value;
    }
}

Answer 2

I noticed that ReSharper's suggestion too and I decided to turn it off. I think that an expression should be used either for its value or for its side-effects, but not both. If you do both, your code will be more confusing. This principle is known as command-query separation.

And I agree with others that using Lazy<T> is even better. If you're still on .Net 3.5 (or older), it shouldn't be that hard to write your own version of that class.