Tôi cần một hệ thống không thể tạo ra va chạm vì vậy tôi không thể ánh xạ nhiều ký tự thành một. Tôi đã kết thúc với:
public static class Extension
{
/// <summary>
/// Characters allowed in a file name. Note that curly braces don't show up here
/// becausee they are used for escaping invalid characters.
/// </summary>
private static readonly HashSet<char> CleanFileNameChars = new HashSet<char>
{
' ', '!', '#', '$', '%', '&', '\'', '(', ')', '+', ',', '-', '.',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '=', '@',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'[', ']', '^', '_', '`',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
};
/// <summary>
/// Creates a clean file name from one that may contain invalid characters in
/// a way that will not collide.
/// </summary>
/// <param name="dirtyFileName">
/// The file name that may contain invalid filename characters.
/// </param>
/// <returns>
/// A file name that does not contain invalid filename characters.
/// </returns>
/// <remarks>
/// <para>
/// Escapes invalid characters by converting their ASCII values to hexadecimal
/// and wrapping that value in curly braces. Curly braces are escaped by doubling
/// them, for example '{' => "{{".
/// </para>
/// <para>
/// Note that although NTFS allows unicode characters in file names, this
/// method does not.
/// </para>
/// </remarks>
public static string CleanFileName(this string dirtyFileName)
{
string EscapeHexString(char c) =>
"{" + (c > 255 ? $"{(uint)c:X4}" : $"{(uint)c:X2}") + "}";
return string.Join(string.Empty,
dirtyFileName.Select(
c =>
c == '{' ? "{{" :
c == '}' ? "}}" :
CleanFileNameChars.Contains(c) ? $"{c}" :
EscapeHexString(c)));
}
}
