I check a file name validation in the following way:
foreach (char c in System.IO.Path.GetInvalidFileNameChars())
{
validFileName = validFileName.Replace(c, '_');
}
Is there a faster way do do so?
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2 Answers
This might be faster, but I hardly think the original would be slow enough to care about...
var invalidChars = Path.GetInvalidFileNameChars();
var fileNameChars = validFileName.ToCharArray();
for (int i = 0; i < fileNameChars.Length; ++i)
if (invalidChars.Contains(fileNameChars[i]))
fileNameChars[i] = '_';
validFileName = new string(fileNameChars);
4 Comments
Rand Random
Any reason you increment the index with
++i, instead of i++?
Matthew Watson
@RandRandom Force of habit from olden C++ days where
++i could be more efficient than i++. Makes no difference either way for C# in this usage due to optimizations, of course. But at least I know I'm being precise about whether I need the value before incrementing or not (++i is clear that I don't)Rand Random
But wouldnt this for loop, skip the fileNameChars[0], because the ++ infront of the i means that you do the increment before you get the value? does this code reach 0. - yeah I know I could test it, but no IDE close by :)
Matthew Watson
@RandRandom No, it doesn't increment it before the start of the loop. It's just executed at the end of each loop iteration, so it doesn't make any difference whether you use
++i or i++. See here for full definition.Whats wrong with that? Two line implementation, and a stack overflow search for this shows your answer matches an accepted answer for another question How to make a valid Windows filename from an arbitrary string?
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