if (File.Exists(f)) { DoSomething(f) }
(or the negation thereof) is an anti-pattern. The file can be deleted or created in between those two statements, so it makes little sense to check its existence like that.
Apart from that, as pointed out in the comments, while File.Exists()
may return true, the actual opening of the file can then still fail for a variety of reasons. So you'll have to repeat the error checking and throwing around the opening of the file.
As you don't want to repeat yourself but instead keep your code DRY, just attempt to open the file and let new FileStream()
throw. Then you can catch the exception, and if you wish, re-throw the original or throw an application-specific exception.
Of course calling File.Exists()
can be justified, but not in this pattern.
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…