编码翻译在某些电脑上不起作用

我正在努力解决将Mazovia编码（旧的波兰编码）转换为Unicode的问题。我使用了mazovia编码类的实现，这里有一个链接。我使用这个类来转换DBF文件中的值，方法是：

        public static string AsUnicode(string text)
        {
           string result =  System.Text.Encoding.Unicode.GetString(
                    System.Text.Encoding.Convert(new Mazovia(),
                                                 System.Text.Encoding.Unicode,
                                                 System.Text.Encoding.GetEncoding(852).GetBytes(text)));

           return result;
        }

在我使用之前，但不知怎么的，几周后它就停止了工作。公共静态字符串AsLatin2（字符串文本）｛

           string result =  System.Text.Encoding.GetEncoding(1250).GetString(
                    System.Text.Encoding.Convert(new Mazovia(),
                                                 System.Text.Encoding.GetEncoding(1250),
                                                 new Mazovia().GetBytes(text)));
           return result;
        }

新的解决方案在我的电脑和我测试过的其他几台电脑上运行良好，但它并不适用于所有设备。在一些网站上，它仍然读着"？"而不是"Ł"之类的标志。

Engoding在波兰语和英语Windows7/8上都能工作，但仅在某些编码上不起作用，我不知道可能有什么问题。有人在编码类方面有类似的问题吗？在不同的Windows操作系统实例上有不同的行为？

这是我正在使用的Mazovia的整个Encodinf实现：

公共密封类MazoviaEncoder:编码器{private Dictionary Translator=new Dictionary（）；

    internal MazoviaEncoder()
    {
        for (byte i = 0x00; i < 0x80; i++)
        {
            char c = (char)i;
            Translator.Add(c, i); // znaki poniżej 128 to standardowe kody ASCII
        }
        for (byte i = 0x00; i < 0x80; i++)
        {
            char c = (char)MazoviaAsUnicode.Content[i];
            Translator.Add(c, (byte)(i + 0x80)); // znaki powyżej 127 to kody zgodne z Mazovią - trzeba użyć słownika translacji
        }
    }
    public override int GetByteCount(char[] chars, int index, int count, bool flush)
    {
        // Mazovia jest jednobajtową stroną kodową, więc ilość bajtów dla podanej długości tekstu "count",
        // jest równa tej długości (jeden unikodowy, dwubajtowy znak równa się jednemu bajtowi Mazovii)
        return count;
    }
    public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex, bool flush)
    {
        byte b;
        for (int i = 0; i < charCount; i++)
        {
            if (!Translator.TryGetValue(chars[charIndex + i], out b))
                b = 0x3F;
            bytes[byteIndex + i] = b;
        }
        return charCount;
    }
}
internal static class MazoviaAsUnicode
{
    public static readonly short[] Content = {
0x00C7, 0x00FC, 0x00E9, 0x00E2, 0x00E4, 0x00E0, 0x0105, 0x00E7,
0x00EA, 0x00EB, 0x00E8, 0x00EF, 0x00EE, 0x0107, 0x00C4, 0x0104,
0x0118, 0x0119, 0x0142, 0x00F4, 0x00F6, 0x0106, 0x00FB, 0x00F9,
0x015A, 0x00D6, 0x00DC, 0x00A2, 0x0141, 0x00A5, 0x015B, 0x0192,
0x0179, 0x017B, 0x00F3, 0x00D3, 0x0144, 0x0143, 0x017A, 0x017C,
0x00BF, 0x2310, 0x00AC, 0x00BD, 0x00BC, 0x00A1, 0x00AB, 0x00BB,
0x2591, 0x2592, 0x2593, 0x2502, 0x2524, 0x2561, 0x2562, 0x2556,
0x2555, 0x2563, 0x2551, 0x2557, 0x255D, 0x255C, 0x255B, 0x2510,
0x2514, 0x2534, 0x252C, 0x251C, 0x2500, 0x253C, 0x255E, 0x255F,
0x255A, 0x2554, 0x2569, 0x2566, 0x2560, 0x2550, 0x256C, 0x2567,
0x2568, 0x2564, 0x2565, 0x2559, 0x2558, 0x2552, 0x2553, 0x256B,
0x256A, 0x2518, 0x250C, 0x2588, 0x2584, 0x258C, 0x2590, 0x2580,
0x03B1, 0x00DF, 0x0393, 0x03C0, 0x03A3, 0x03C3, 0x00B5, 0x03C4,
0x03A6, 0x0398, 0x03A9, 0x03B4, 0x221E, 0x03C6, 0x03B5, 0x2229,
0x2261, 0x00B1, 0x2265, 0x2264, 0x2320, 0x2321, 0x00F7, 0x2248,
0x00B0, 0x2219, 0x00B7, 0x221A, 0x207F, 0x00B2, 0x25A0, 0x00A0};
}
public sealed class MazoviaDecoder : Decoder
{
    private char[] Translator = new char[256];
    internal MazoviaDecoder()
    {
        for (byte i = 0x00; i < 0x80; i++)
        {
            char c = (char)i;
            Translator[i] = c; // znaki poniżej 128 to standardowe kody ASCII
        }
        for (byte i = 0x00; i < 0x80; i++)
        {
            char c = (char)MazoviaAsUnicode.Content[i];
            Translator[i + 0x80] = c; // znaki powyżej 127 to kody zgodne z Mazovią - trzeba użyć słownika translacji
        }
    }
    public override int GetCharCount(byte[] bytes, int index, int count)
    {
        // Mazovia jest jednobajtową stroną kodową, więc ilość znaków dla podanej ilości bajtów "count",
        // jest równa tej właśnie ilości (jeden bajt Mazovii równa się dwubajtowemu znakowi)
        return count;
    }
    public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
    {
        for (int i = 0; i < byteCount; i++)
            chars[charIndex + i] = Translator[bytes[byteIndex + i]];
        return byteCount;
    }
}
public class Mazovia : System.Text.Encoding
{
    public static MazoviaEncoder GetMazoviaEncoder()
    {
        return new MazoviaEncoder();
    }
    public static MazoviaDecoder GetMazoviaDecoder()
    {
        return new MazoviaDecoder();
    }
    public override int GetByteCount(char[] chars, int index, int count)
    {
        return GetMazoviaEncoder().GetByteCount(chars, index, count, false);
    }
    public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
    {
        return GetMazoviaEncoder().GetBytes(chars, charIndex, charCount, bytes, byteIndex, false);
    }
    public override int GetCharCount(byte[] bytes, int index, int count)
    {
        return GetMazoviaDecoder().GetCharCount(bytes, index, count);
    }
    public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
    {
        return GetMazoviaDecoder().GetChars(bytes, byteIndex, byteCount, chars, charIndex);
    }
    public override int GetMaxByteCount(int charCount)
    {
        return charCount;
    }
    public override int GetMaxCharCount(int byteCount)
    {
        return byteCount;
    }
}
    public class External
    {
        [Microsoft.SqlServer.Server.SqlFunction()]
        public static SqlString AsMazovia(SqlString text)
        {
            if (text.IsNull)
                return SqlString.Null;
            byte[] b = text.GetNonUnicodeBytes();
            char[] c = new char[b.Length];
            Mazovia Mazovia = new Mazovia();
            Mazovia.GetChars(b, 0, b.Length, c, 0);
            StringBuilder sb = new StringBuilder(b.Length);
            foreach (var i in c)
                sb.Append(i);
            SqlString result = new SqlString(sb.ToString());
            return result.Value;
        }
        public static string AsUnicode(string text)
        {
           string result =  System.Text.Encoding.Unicode.GetString(
                    System.Text.Encoding.Convert(new Mazovia(),
                                                 System.Text.Encoding.Unicode,
                                                 System.Text.Encoding.GetEncoding(852).GetBytes(text)));

           return result;
        }
    }

我用来从.DBF文件加载数据的代码如下：

            string strAccessConn = @"Provider=vfpoledb;uid=admin;Collating Sequence=machine;Data                                                                           Source=...'latin2;CodePage=852";
            string strAccessSelect = "SELECT NAME FROM TABLE";
            DataSet myDataSet = new DataSet();
            OleDbConnection myAccessConn = null;
                myAccessConn = new OleDbConnection(strAccessConn);
                OleDbCommand myAccessCommand = new OleDbCommand(strAccessSelect, myAccessConn);
                OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand);
                myAccessConn.Open();
                myDataAdapter.Fill(myDataSet, "TABLE");
                return null;
                myAccessConn.Close();
            DataTableCollection dta = myDataSet.Tables;
            foreach (DataTable dt in dta)
            {
...
}

这是bith-odbc和oleDB使用的许多提供者之一。