Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
209 views
in Technique[技术] by (71.8m points)

c# - null coalescing operator in accessor method

i was looking around in stackoverflow whether putting null coalescing operators within an accessor method has any performance implications.

Before:

private Uri _Url;
public Uri Url
{
    if(_Url == null)
        _Url = new Uri(Utilities.GenerateUri());
    return _Url;
}

After:

private Uri _Url;
public Uri Url 
{
    get 
    {
        return _Url = _Url ?? new Uri(Utilities.GenerateUri());
    }
}

I'm not even sure if the syntax is correct, but when i debug, the private object is set.

Before anyone ask what's the point of doing it, we were debating internally whether to write for readability (the first looks more readable to me), or to write for performance.

I don't know whether the compiler will optimize ?? better than a manual null check all the time. Micro-optimization is bad, but i am just curious

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

You can actually write this as:

return _Url ?? (_Url = new Uri(Utilities.GenerateUri()));

As far as performance goes, it is practically the same thing as using if, so no difference.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...