C# Sanitize File Name

Question

I recently have been moving a bunch of MP3s from various locations into a repository. I had been constructing the new file names using the ID3 tags (thanks, TagLib-Sharp!),

Answer 1

I wanted to retain the characters in some way, not just simply replace the character with an underscore.

One way I thought was to replace the characters with similar looking characters which are (in my situation), unlikely to be used as regular characters. So I took the list of invalid characters and found look-a-likes.

The following are functions to encode and decode with the look-a-likes.

This code does not include a complete listing for all System.IO.Path.GetInvalidFileNameChars() characters. So it is up to you to extend or utilize the underscore replacement for any remaining characters.

private static Dictionary EncodeMapping()
{
    //-- Following characters are invalid for windows file and folder names.
    //-- \/:*?"<>|
    Dictionary dic = new Dictionary();
    dic.Add(@"\", "Ì"); // U+OOCC
    dic.Add("/", "Í"); // U+OOCD
    dic.Add(":", "¦"); // U+00A6
    dic.Add("*", "¤"); // U+00A4
    dic.Add("?", "¿"); // U+00BF
    dic.Add(@"""", "ˮ"); // U+02EE
    dic.Add("<", "«"); // U+00AB
    dic.Add(">", "»"); // U+00BB
    dic.Add("|", "│"); // U+2502
    return dic;
}

public static string Escape(string name)
{
    foreach (KeyValuePair replace in EncodeMapping())
    {
        name = name.Replace(replace.Key, replace.Value);
    }

    //-- handle dot at the end
    if (name.EndsWith(".")) name = name.CropRight(1) + "°";

    return name;
}

public static string UnEscape(string name)
{
    foreach (KeyValuePair replace in EncodeMapping())
    {
        name = name.Replace(replace.Value, replace.Key);
    }

    //-- handle dot at the end
    if (name.EndsWith("°")) name = name.CropRight(1) + ".";

    return name;
}

You can select your own look-a-likes. I used the Character Map app in windows to select mine %windir%\system32\charmap.exe

As I make adjustments through discovery, I will update this code.