Can.NET convertir Unicode en ASCII pour supprimer "citations intelligentes", etc?

merci à tous pour vos réponses très utiles. Je me rends compte que la vraie question n'est pas "comment puis - je convertir N'importe quel caractère Unicode dans son repli ASCII" - la question Est "Comment puis-je convertir les caractères Unicode mes clients se plaignent dans leurs retombées ASCII" ?

en d'autres termes - nous n'avons pas besoin d'une solution polyvalente; nous avons besoin d'une solution qui fonctionne 99% du temps, pour les clients anglophones qui collent du contenu de langue anglaise à partir de Word et d'autres sites web dans notre application. À cette fin, j'ai analysé huit années de messages envoyés par notre système à la recherche de caractères qui ne sont pas représentables dans l'encodage ASCII, en utilisant ce test:

///<summary>Determine whether the supplied character is 
///using ASCII encoding.</summary>
bool IsAscii(char inputChar) {
    var ascii = new ASCIIEncoding();
    var asciiChar = (char)(ascii.GetBytes(inputChar.ToString())[0]);
    return(asciiChar == inputChar);
}

j'ai ensuite parcouru l'ensemble résultant de caractères non brevetables et j'ai assigné manuellement une chaîne de remplacement appropriée. Le tout est enfermé dans une méthode d'extension, de sorte que vous pouvez appeler myString.Asciify () pour convertir votre chaîne de caractères en raisonnable Approximation d'encodage ASCII.

public static class StringExtensions {
    private static readonly Dictionary<char, string> Replacements = new Dictionary<char, string>();
    /// <summary>Returns the specified string with characters not representable in ASCII codepage 437 converted to a suitable representative equivalent.  Yes, this is lossy.</summary>
    /// <param name="s">A string.</param>
    /// <returns>The supplied string, with smart quotes, fractions, accents and punctuation marks 'normalized' to ASCII equivalents.</returns>
    /// <remarks>This method is lossy. It's a bit of a hack that we use to get clean ASCII text for sending to downlevel e-mail clients.</remarks>
    public static string Asciify(this string s) {
        return (String.Join(String.Empty, s.Select(c => Asciify(c)).ToArray()));
    }

    private static string Asciify(char x) {
        return Replacements.ContainsKey(x) ? (Replacements[x]) : (x.ToString());
    }

    static StringExtensions() {
        Replacements['’'] = "'"; // 75151 occurrences
        Replacements['–'] = "-"; // 23018 occurrences
        Replacements['‘'] = "'"; // 9783 occurrences
        Replacements['”'] = "\""; // 6938 occurrences
        Replacements['“'] = "\""; // 6165 occurrences
        Replacements['…'] = "..."; // 5547 occurrences
        Replacements['£'] = "GBP"; // 3993 occurrences
        Replacements['•'] = "*"; // 2371 occurrences
        Replacements[' '] = " "; // 1529 occurrences
        Replacements['é'] = "e"; // 878 occurrences
        Replacements['ï'] = "i"; // 328 occurrences
        Replacements['´'] = "'"; // 226 occurrences
        Replacements['—'] = "-"; // 133 occurrences
        Replacements['·'] = "*"; // 132 occurrences
        Replacements['„'] = "\""; // 102 occurrences
        Replacements['€'] = "EUR"; // 95 occurrences
        Replacements['®'] = "(R)"; // 91 occurrences
        Replacements['¹'] = "(1)"; // 80 occurrences
        Replacements['«'] = "\""; // 79 occurrences
        Replacements['è'] = "e"; // 79 occurrences
        Replacements['á'] = "a"; // 55 occurrences
        Replacements['™'] = "TM"; // 54 occurrences
        Replacements['»'] = "\""; // 52 occurrences
        Replacements['ç'] = "c"; // 52 occurrences
        Replacements['½'] = "1/2"; // 48 occurrences
        Replacements['­'] = "-"; // 39 occurrences
        Replacements['°'] = " degrees "; // 33 occurrences
        Replacements['ä'] = "a"; // 33 occurrences
        Replacements['É'] = "E"; // 31 occurrences
        Replacements['‚'] = ","; // 31 occurrences
        Replacements['ü'] = "u"; // 30 occurrences
        Replacements['í'] = "i"; // 28 occurrences
        Replacements['ë'] = "e"; // 26 occurrences
        Replacements['ö'] = "o"; // 19 occurrences
        Replacements['à'] = "a"; // 19 occurrences
        Replacements['¬'] = " "; // 17 occurrences
        Replacements['ó'] = "o"; // 15 occurrences
        Replacements['â'] = "a"; // 13 occurrences
        Replacements['ñ'] = "n"; // 13 occurrences
        Replacements['ô'] = "o"; // 10 occurrences
        Replacements['¨'] = ""; // 10 occurrences
        Replacements['å'] = "a"; // 8 occurrences
        Replacements['ã'] = "a"; // 8 occurrences
        Replacements['ˆ'] = ""; // 8 occurrences
        Replacements['©'] = "(c)"; // 6 occurrences
        Replacements['Ä'] = "A"; // 6 occurrences
        Replacements['Ï'] = "I"; // 5 occurrences
        Replacements['ò'] = "o"; // 5 occurrences
        Replacements['ê'] = "e"; // 5 occurrences
        Replacements['î'] = "i"; // 5 occurrences
        Replacements['Ü'] = "U"; // 5 occurrences
        Replacements['Á'] = "A"; // 5 occurrences
        Replacements['ß'] = "ss"; // 4 occurrences
        Replacements['¾'] = "3/4"; // 4 occurrences
        Replacements['È'] = "E"; // 4 occurrences
        Replacements['¼'] = "1/4"; // 3 occurrences
        Replacements['†'] = "+"; // 3 occurrences
        Replacements['³'] = "'"; // 3 occurrences
        Replacements['²'] = "'"; // 3 occurrences
        Replacements['Ø'] = "O"; // 2 occurrences
        Replacements['¸'] = ","; // 2 occurrences
        Replacements['Ë'] = "E"; // 2 occurrences
        Replacements['ú'] = "u"; // 2 occurrences
        Replacements['Ö'] = "O"; // 2 occurrences
        Replacements['û'] = "u"; // 2 occurrences
        Replacements['Ú'] = "U"; // 2 occurrences
        Replacements['Œ'] = "Oe"; // 2 occurrences
        Replacements['º'] = "?"; // 1 occurrences
        Replacements['‰'] = "0/00"; // 1 occurrences
        Replacements['Å'] = "A"; // 1 occurrences
        Replacements['ø'] = "o"; // 1 occurrences
        Replacements['˜'] = "~"; // 1 occurrences
        Replacements['æ'] = "ae"; // 1 occurrences
        Replacements['ù'] = "u"; // 1 occurrences
        Replacements['‹'] = "<"; // 1 occurrences
        Replacements['±'] = "+/-"; // 1 occurrences
    }
}

Notez qu'il existe certains plutôt étrange de base - comme celui-ci:

Replacements['³'] = "'"; // 3 occurrences
Replacements['²'] = "'"; // 3 occurrences

c'est parce qu'un de nos utilisateurs a un programme qui convertit des citations intelligentes ouvertes/fermées en 2 et 3 (comme : il a dit 2hello3) et personne ne les a jamais utilisées pour représenter l'exponentiation, donc cela fonctionnera probablement assez bien pour nous, mais YMMV.