Creating valid file extension list

Question

I'm applying a function to specific file formats

string extension = Path.GetExtension(files[i]);
if (extension == ".txt")
{
    DoSomething(files[i]);
}

But I have too many file extension, not only txt. What is the basic way to create a white list and check if it's included on that list?

This seems similar to this other answer: http://stackoverflow.com/a/17736237/2557263 — Alejandro, Aug 15 '15 at 17:28

score 3 · Accepted Answer · edited May 23 '17 at 10:27

3

you can create a white list and check if extension is inside it or not

var whitelist = new[]
{
    ".txt", ".bat", ".con"
};

string extension = Path.GetExtension(files[i]);
if (whitelist.Contains(extension))
{
    DoSomething(files[i]);
}

if your white list size becomes large (more than 20) try using HashSet for better performance

edited May 23 '17 at 10:27

Community

1
1

answered Aug 15 '15 at 17:20

Hamid Pourjam

20,441
9
58
74

score 0 · Answer 2 · edited Feb 07 '20 at 01:41

 List<string> fileExtensions = new List<string>();
                      fileExtensions.AddRange(".txt,.png,.bmp,.pdf".Split(','));
                      string extension = Path.GetExtension(files[i]);
                      if (fileExtensions.Contains(extension, StringComparison.OrdinalIgnoreCase))
                      {
                        //  DoSomething(files[i]);
                      }

Creating valid file extension list

2 Answers2