I reverse engineered the Microsoft System.Net.WebUtility class from .NET 4.0 using Reflector (I think they'd be ok with it given the circumstances). So you could either use .NET 4.0 Client Framework (which now has this new class) or use the code here.
As long as you use a strong name on your assembly etc., you'll be safe enough. Here:
/// <summary>
/// Taken from System.Net in 4.0, useful until we move to .NET 4.0 - needed for Client Profile
/// </summary>
public static class WebUtility
{
// Fields
private static char[] _htmlEntityEndingChars = new char[] { ';', '&' };
// Methods
public static string HtmlDecode(string value)
{
if (string.IsNullOrEmpty(value))
{
return value;
}
if (value.IndexOf('&') < 0)
{
return value;
}
StringWriter output = new StringWriter(CultureInfo.InvariantCulture);
HtmlDecode(value, output);
return output.ToString();
}
public static void HtmlDecode(string value, TextWriter output)
{
if (value != null)
{
if (output == null)
{
throw new ArgumentNullException("output");
}
if (value.IndexOf('&') < 0)
{
output.Write(value);
}
else
{
int length = value.Length;
for (int i = 0; i < length; i++)
{
char ch = value[i];
if (ch == '&')
{
int num3 = value.IndexOfAny(_htmlEntityEndingChars, i + 1);
if ((num3 > 0) && (value[num3] == ';'))
{
string entity = value.Substring(i + 1, (num3 - i) - 1);
if ((entity.Length > 1) && (entity[0] == '#'))
{
ushort num4;
if ((entity[1] == 'x') || (entity[1] == 'X'))
{
ushort.TryParse(entity.Substring(2), NumberStyles.AllowHexSpecifier, (IFormatProvider)NumberFormatInfo.InvariantInfo, out num4);
}
else
{
ushort.TryParse(entity.Substring(1), NumberStyles.Integer, (IFormatProvider)NumberFormatInfo.InvariantInfo, out num4);
}
if (num4 != 0)
{
ch = (char)num4;
i = num3;
}
}
else
{
i = num3;
char ch2 = HtmlEntities.Lookup(entity);
if (ch2 != '\0')
{
ch = ch2;
}
else
{
output.Write('&');
output.Write(entity);
output.Write(';');
goto Label_0117;
}
}
}
}
output.Write(ch);
Label_0117: ;
}
}
}
}
public static string HtmlEncode(string value)
{
if (string.IsNullOrEmpty(value))
{
return value;
}
if (IndexOfHtmlEncodingChars(value, 0) == -1)
{
return value;
}
StringWriter output = new StringWriter(CultureInfo.InvariantCulture);
HtmlEncode(value, output);
return output.ToString();
}
public static unsafe void HtmlEncode(string value, TextWriter output)
{
if (value != null)
{
if (output == null)
{
throw new ArgumentNullException("output");
}
int num = IndexOfHtmlEncodingChars(value, 0);
if (num == -1)
{
output.Write(value);
}
else
{
int num2 = value.Length - num;
fixed (char* str = value)
{
char* chPtr = str;
char* chPtr2 = chPtr;
while (num-- > 0)
{
chPtr2++;
output.Write(chPtr2[0]);
}
while (num2-- > 0)
{
chPtr2++;
char ch = chPtr2[0];
if (ch <= '>')
{
switch (ch)
{
case '&':
{
output.Write("&");
continue;
}
case '\'':
{
output.Write("'");
continue;
}
case '"':
{
output.Write(""");
continue;
}
case '<':
{
output.Write("<");
continue;
}
case '>':
{
output.Write(">");
continue;
}
}
output.Write(ch);
continue;
}
if ((ch >= '\x00a0') && (ch < 'Ā'))
{
output.Write("&#");
output.Write(((int)ch).ToString(NumberFormatInfo.InvariantInfo));
output.Write(';');
}
else
{
output.Write(ch);
}
}
}
}
}
}
private static unsafe int IndexOfHtmlEncodingChars(string s, int startPos)
{
int num = s.Length - startPos;
fixed (char* str = s)
{
char* chPtr = str;
char* chPtr2 = chPtr + startPos;
while (num > 0)
{
char ch = chPtr2[0];
if (ch <= '>')
{
switch (ch)
{
case '&':
case '\'':
case '"':
case '<':
case '>':
return (s.Length - num);
case '=':
goto Label_0086;
}
}
else if ((ch >= '\x00a0') && (ch < 'Ā'))
{
return (s.Length - num);
}
Label_0086:
chPtr2++;
num--;
}
}
return -1;
}
// Nested Types
private static class HtmlEntities
{
// Fields
private static string[] _entitiesList = new string[] {
"\"-quot", "&-amp", "'-apos", "<-lt", ">-gt", "\x00a0-nbsp", "\x00a1-iexcl", "\x00a2-cent", "\x00a3-pound", "\x00a4-curren", "\x00a5-yen", "\x00a6-brvbar", "\x00a7-sect", "\x00a8-uml", "\x00a9-copy", "\x00aa-ordf",
"\x00ab-laquo", "\x00ac-not", "\x00ad-shy", "\x00ae-reg", "\x00af-macr", "\x00b0-deg", "\x00b1-plusmn", "\x00b2-sup2", "\x00b3-sup3", "\x00b4-acute", "\x00b5-micro", "\x00b6-para", "\x00b7-middot", "\x00b8-cedil", "\x00b9-sup1", "\x00ba-ordm",
"\x00bb-raquo", "\x00bc-frac14", "\x00bd-frac12", "\x00be-frac34", "\x00bf-iquest", "\x00c0-Agrave", "\x00c1-Aacute", "\x00c2-Acirc", "\x00c3-Atilde", "\x00c4-Auml", "\x00c5-Aring", "\x00c6-AElig", "\x00c7-Ccedil", "\x00c8-Egrave", "\x00c9-Eacute", "\x00ca-Ecirc",
"\x00cb-Euml", "\x00cc-Igrave", "\x00cd-Iacute", "\x00ce-Icirc", "\x00cf-Iuml", "\x00d0-ETH", "\x00d1-Ntilde", "\x00d2-Ograve", "\x00d3-Oacute", "\x00d4-Ocirc", "\x00d5-Otilde", "\x00d6-Ouml", "\x00d7-times", "\x00d8-Oslash", "\x00d9-Ugrave", "\x00da-Uacute",
"\x00db-Ucirc", "\x00dc-Uuml", "\x00dd-Yacute", "\x00de-THORN", "\x00df-szlig", "\x00e0-agrave", "\x00e1-aacute", "\x00e2-acirc", "\x00e3-atilde", "\x00e4-auml", "\x00e5-aring", "\x00e6-aelig", "\x00e7-ccedil", "\x00e8-egrave", "\x00e9-eacute", "\x00ea-ecirc",
"\x00eb-euml", "\x00ec-igrave", "\x00ed-iacute", "\x00ee-icirc", "\x00ef-iuml", "\x00f0-eth", "\x00f1-ntilde", "\x00f2-ograve", "\x00f3-oacute", "\x00f4-ocirc", "\x00f5-otilde", "\x00f6-ouml", "\x00f7-divide", "\x00f8-oslash", "\x00f9-ugrave", "\x00fa-uacute",
"\x00fb-ucirc", "\x00fc-uuml", "\x00fd-yacute", "\x00fe-thorn", "\x00ff-yuml", "Œ-OElig", "œ-oelig", "Š-Scaron", "š-scaron", "Ÿ-Yuml", "ƒ-fnof", "ˆ-circ", "˜-tilde", "Α-Alpha", "Β-Beta", "Γ-Gamma",
"Δ-Delta", "Ε-Epsilon", "Ζ-Zeta", "Η-Eta", "Θ-Theta", "Ι-Iota", "Κ-Kappa", "Λ-Lambda", "Μ-Mu", "Ν-Nu", "Ξ-Xi", "Ο-Omicron", "Π-Pi", "Ρ-Rho", "Σ-Sigma", "Τ-Tau",
"Υ-Upsilon", "Φ-Phi", "Χ-Chi", "Ψ-Psi", "Ω-Omega", "α-alpha", "β-beta", "γ-gamma", "δ-delta", "ε-epsilon", "ζ-zeta", "η-eta", "θ-theta", "ι-iota", "κ-kappa", "λ-lambda",
"μ-mu", "ν-nu", "ξ-xi", "ο-omicron", "π-pi", "ρ-rho", "ς-sigmaf", "σ-sigma", "τ-tau", "υ-upsilon", "φ-phi", "χ-chi", "ψ-psi", "ω-omega", "ϑ-thetasym", "ϒ-upsih",
"ϖ-piv", " -ensp", " -emsp", " -thinsp", "-zwnj", "-zwj", "-lrm", "-rlm", "–-ndash", "—-mdash", "‘-lsquo", "’-rsquo", "‚-sbquo", "“-ldquo", "”-rdquo", "„-bdquo",
"†-dagger", "‡-Dagger", "•-bull", "…-hellip", "‰-permil", "′-prime", "″-Prime", "‹-lsaquo", "›-rsaquo", "‾-oline", "⁄-frasl", "€-euro", "ℑ-image", "℘-weierp", "ℜ-real", "™-trade",
"ℵ-alefsym", "←-larr", "↑-uarr", "→-rarr", "↓-darr", "↔-harr", "↵-crarr", "⇐-lArr", "⇑-uArr", "⇒-rArr", "⇓-dArr", "⇔-hArr", "∀-forall", "∂-part", "∃-exist", "∅-empty",
"∇-nabla", "∈-isin", "∉-notin", "∋-ni", "∏-prod", "∑-sum", "−-minus", "∗-lowast", "√-radic", "∝-prop", "∞-infin", "∠-ang", "∧-and", "∨-or", "∩-cap", "∪-cup",
"∫-int", "∴-there4", "∼-sim", "≅-cong", "≈-asymp", "≠-ne", "≡-equiv", "≤-le", "≥-ge", "⊂-sub", "⊃-sup", "⊄-nsub", "⊆-sube", "⊇-supe", "⊕-oplus", "⊗-otimes",
"⊥-perp", "⋅-sdot", "⌈-lceil", "⌉-rceil", "⌊-lfloor", "⌋-rfloor", "〈-lang", "〉-rang", "◊-loz", "♠-spades", "♣-clubs", "♥-hearts", "♦-diams"
};
private static Dictionary<string, char> _lookupTable = GenerateLookupTable();
// Methods
private static Dictionary<string, char> GenerateLookupTable()
{
Dictionary<string, char> dictionary = new Dictionary<string, char>(StringComparer.Ordinal);
foreach (string str in _entitiesList)
{
dictionary.Add(str.Substring(2), str[0]);
}
return dictionary;
}
public static char Lookup(string entity)
{
char ch;
_lookupTable.TryGetValue(entity, out ch);
return ch;
}
}
}
