Using Directory.GetFiles as a condition to check if certain files are inside the directory , c# scripts

Question

How can I check all the files inside a directory that contains the (.jpg,.jpeg,.png and .pdf) file format and then would only proceed to store the filenames inside a variables if those files exist? I tried using this code but it does not work. Reason why I said it does not work is because the process I put inside is not being initiated. Is there something wrong with my code? Please enlighten me or lead me to the proper way. All help is appreciated!

if(Directory.GetFiles(directory).All(x=> string.Compare(Path.GetExtension(x),"*.pdf", StringComparison.CurrentCultureIgnoreCase) == 0) && Directory.GetFiles(directory).All(x=> string.Compare(Path.GetExtension(x),"*.jpg", StringComparison.CurrentCultureIgnoreCase))
{
    // insert process here of getting the file names that has the extension of .jpg,.jpeg,.png and .pdf
}

"it does not work" why not? Does it throw an exception, if so which? Does it silently fail, if so is there log output? Does it not find any files? Please [edit] your question to include *why* it's not working — MindSwipe, May 20 '20 at 06:33
That being said, I see you're using [this](https://learn.microsoft.com/en-us/dotnet/api/system.string.compare?view=netcore-3.1#System_String_Compare_System_String_System_String_System_StringComparison_) overload of the `string.Compare` method, which does not accept a regex, instead two strings to compare. So your comparing the extension of "fooBar.png" (so ".png") to "*.png", which is obviously not the same — MindSwipe, May 20 '20 at 06:36
It is unclear do you want to process files if **all** or **any** files in the directory of the specified extensions? — Iliar Turdushev, May 20 '20 at 06:37
I want to process all the files that contains the said extensions. @MindSwipe I have in my other code Directory.GetFiles but with a zip file and used " *.zip " and it worked , so I assumed that using " *.jpg" would work as well — devbbg, May 20 '20 at 06:43
Yes, `Directory.GetFiles("...", "*.zip")` works, because of [this](https://learn.microsoft.com/en-us/dotnet/api/system.io.directory.getfiles?view=netcore-3.1#System_IO_Directory_GetFiles_System_String_System_String_) overload. Whoever `string.Compare` has no similar overload. I'm currently writing an answer, hold tight — MindSwipe, May 20 '20 at 06:46
@devbbg Please, refer this link https://stackoverflow.com/q/163162/12833205. Does it answer your question? — Iliar Turdushev, May 20 '20 at 06:54
@IliarTurdushev im sorry it doesn't :( I tried the code and tried to output them using foreach then it returned me this one System.Linq.Enumerable+WhereEnumerableIterator`1[System.String] — devbbg, May 20 '20 at 07:14

MindSwipe · Accepted Answer · 2020-05-20T08:44:47.450

The overload of the string compare method you're using does not accept a pattern to compare to, instead a second string to compare the first to. Which means if you have a file "fooBar.png" in your directory, your eventually comparing it's extension (so ".png") to "*.png", which is not the same.

You also said you want to get all file names that end with one of a number of specified extensions, but your using .All(...), which only returns true if all items inside the enumeration match the given expression. So

All(x=> string.Compare(Path.GetExtension(x),"*.pdf", StringComparison.CurrentCultureIgnoreCase) == 0)

would only return true if all files inside the directory were pdf files.

There is also not necessarily a problem, but something sub-optimal in your code: Your reading the same content from disk multiple times, which is as said, sub-optimal.

That being said, here is some updated code to fix your problem:

var acceptedFileTypes = new List<string>
{
    ".png",
    ".pdf",
    ...
};

// Get all files in the specified directory
var filesInDirectory = Directory.GetFiles(directory);

// Only select those with accepted file extensions
// Explicit type for better understanding
List<string> supportedFiles = filesInDirectory.Where(
    file => acceptedFileTypes.Contains(Path.GetExtension(file))
).ToList();

// Do something with the supportedFiles
// e.g print them to the console:
foreach (var file in supportedFiles)
{
    Console.WriteLine($"Found supported file: {file}");
}

You can do whatever you want with this, put it in a method and swap acceptedFileTypes for a static member, or put this in a static class of its own etc.
As well you can add new file types easily by appending the List

ill check on this codes now, thank you so much for the help and the explanations as well! Will get back on you once done. — devbbg, May 20 '20 at 07:58
it worked perfectly however I have minor changes, and would like you to edit it out. it should be Path.GetExtension and in the Console.WriteLine I did it like this Console.WriteLine("File name: {0}", file) — devbbg, May 20 '20 at 08:25
I just edited the question to use `Path.GetExtension` (brain fart moment). But I wont be editing the `Console.WriteLine` to use formatting, as string interpolation (the `$` and `{...}`) get compiled as `string.Format(...)` as it is simply syntactic sugar and makes no difference (although it isn't available in C# < 6 and .NET Framework < 4.5) — MindSwipe, May 20 '20 at 08:52

Using Directory.GetFiles as a condition to check if certain files are inside the directory , c# scripts

1 Answers1