Довольно просто: .NET 1.1 «исправлен»: он не изменится. Вы берете кодировки 2.0 и проверяете, присутствовали ли они в версии 1.1. Например:
string[] encs = new string[] {
"IBM037", "IBM437", "IBM500", "ASMO-708", "DOS-720", "ibm737",
"ibm775", "ibm850", "ibm852", "IBM855", "ibm857", "IBM00858",
"IBM860", "ibm861", "DOS-862", "IBM863", "IBM864", "IBM865",
"cp866", "ibm869", "IBM870", "windows-874", "cp875",
"shift_jis", "gb2312", "ks_c_5601-1987", "big5", "IBM1026",
"IBM01047", "IBM01140", "IBM01141", "IBM01142", "IBM01143",
"IBM01144", "IBM01145", "IBM01146", "IBM01147", "IBM01148",
"IBM01149", "utf-16", "utf-16BE", "windows-1250",
"windows-1251", "Windows-1252", "windows-1253", "windows-1254",
"windows-1255", "windows-1256", "windows-1257", "windows-1258",
"Johab", "macintosh", "x-mac-japanese", "x-mac-chinesetrad",
"x-mac-korean", "x-mac-arabic", "x-mac-hebrew", "x-mac-greek",
"x-mac-cyrillic", "x-mac-chinesesimp", "x-mac-romanian",
"x-mac-ukrainian", "x-mac-thai", "x-mac-ce", "x-mac-icelandic",
"x-mac-turkish", "x-mac-croatian", "utf-32", "utf-32BE",
"x-Chinese-CNS", "x-cp20001", "x-Chinese-Eten", "x-cp20003",
"x-cp20004", "x-cp20005", "x-IA5", "x-IA5-German",
"x-IA5-Swedish", "x-IA5-Norwegian", "us-ascii", "x-cp20261",
"x-cp20269", "IBM273", "IBM277", "IBM278", "IBM280", "IBM284",
"IBM285", "IBM290", "IBM297", "IBM420", "IBM423", "IBM424",
"x-EBCDIC-KoreanExtended", "IBM-Thai", "koi8-r", "IBM871",
"IBM880", "IBM905", "IBM00924", "EUC-JP", "x-cp20936",
"x-cp20949", "cp1025", "koi8-u", "iso-8859-1", "iso-8859-2",
"iso-8859-3", "iso-8859-4", "iso-8859-5", "iso-8859-6",
"iso-8859-7", "iso-8859-8", "iso-8859-9", "iso-8859-13",
"iso-8859-15", "x-Europa", "iso-8859-8-i", "iso-2022-jp",
"csISO2022JP", "iso-2022-jp", "iso-2022-kr", "x-cp50227",
"euc-jp", "EUC-CN", "euc-kr", "hz-gb-2312", "GB18030",
"x-iscii-de", "x-iscii-be", "x-iscii-ta", "x-iscii-te",
"x-iscii-as", "x-iscii-or", "x-iscii-ka", "x-iscii-ma",
"x-iscii-gu", "x-iscii-pa", "utf-7", "utf-8"
};
и
foreach (string enc in encs)
{
try {
Encoding.GetEncoding(enc);
} catch {
Console.WriteLine("Missing {0}", enc);
}
}
(да, это полный список кодировок, присутствующих в .NET 4.0 ... Если вам нужно их в «числовом» значении, это будет довольно легко сделать) Затем вы берете те, которые не работают, и убираете их из этого списка.
Для их генерации (минимум .NET 2.0 и C # 3.0):
var encs = Encoding.GetEncodings().Select(p => p.Name);
//var encs = Encoding.GetEncodings().Select(p => p.CodePage);
var sb = new StringBuilder("var encs = new[] {");
foreach (var enc in encs) {
sb.Append(" \"" + enc + "\",");
//sb.Append(" " + enc + ",");
}
sb.Length--;
sb.Append(" };");
var str = sb.ToString();
Console.WriteLine(str);