Question

I need a method that could tell me if a file is image, audio or video file. Can I do this with C#?

Answer 1

It depends how robust you want it to be.

The simplest way to do it is to check the extension, like this:

static string[] mediaExtensions = {
    ".PNG", ".JPG", ".JPEG", ".BMP", ".GIF", //etc
    ".WAV", ".MID", ".MIDI", ".WMA", ".MP3", ".OGG", ".RMA", //etc
    ".AVI", ".MP4", ".DIVX", ".WMV", //etc
};

static bool IsMediaFile(string path) {
    return -1 != Array.IndexOf(mediaExtensions, Path.GetExtension(path).ToUpperInvariant());
}

EDIT: For those who really want LINQ, here it is:

return mediaExtensions.Contains(Path.GetExtension(path), StringComparer.OrdinalIgnoreCase);

Note that a file’s extension is not a reliable indicator of its content; anyone can rename a file and change its extension.

If you don’t have the extension, or if you don’t trust it, you can read the beginning of the file and see if it matches file signatures for common media formats.