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Is there an easy way to extract text from an Rtf string without using RichTextBox?
Example:
{\rtf1\ansi\ansicpg1252\uc1\htmautsp\deff2{\fonttbl{\f0\fcharset0 Times New Roman;}{\f2\fcharset0 Segoe UI;}}{\colortbl\red0\green0\blue0;\red255\green255\blue255;}\loch\hich\dbch\pard\plain\ltrpar\itap0{\lang1033\fs18\f2\cf0 \cf0\ql{\f2 {\lang2070\ltrch foo}\li0\ri0\sa0\sb0\fi0\ql\par}
{\f2 {\lang2070\ltrch bar }\li0\ri0\sa0\sb0\fi0\ql\par}
}
}
should return:
foo
bar
226
On the File tab, choose Options > Mail. Under Compose messages, in the Compose messages in this format list, click HTML, Rich Text, or Plain Text.
Rich Text Format (RTF) is a text formatting language devised by Microsoft Corporation. You can represent character, paragraph, and document format attributes using plain text with interspersed RTF commands, groups, and escape sequences.
How to do it in pure C# without any references to other libraries:
This guy wrote a class that strips RTF to plain text just as OP requested. Here is the source
This is his code:
/// <summary>
/// Rich Text Stripper
/// </summary>
/// <remarks>
/// Translated from Python located at:
/// http://stackoverflow.com/a/188877/448
/// </remarks>
public static class RichTextStripper
{
private class StackEntry
{
public int NumberOfCharactersToSkip { get; set; }
public bool Ignorable { get; set; }
public StackEntry(int numberOfCharactersToSkip, bool ignorable)
{
NumberOfCharactersToSkip = numberOfCharactersToSkip;
Ignorable = ignorable;
}
}
private static readonly Regex _rtfRegex = new Regex(@"\\([a-z]{1,32})(-?\d{1,10})?[ ]?|\\'([0-9a-f]{2})|\\([^a-z])|([{}])|[\r\n]+|(.)", RegexOptions.Singleline | RegexOptions.IgnoreCase);
private static readonly List<string> destinations = new List<string>
{
"aftncn","aftnsep","aftnsepc","annotation","atnauthor","atndate","atnicn","atnid",
"atnparent","atnref","atntime","atrfend","atrfstart","author","background",
"bkmkend","bkmkstart","blipuid","buptim","category","colorschememapping",
"colortbl","comment","company","creatim","datafield","datastore","defchp","defpap",
"do","doccomm","docvar","dptxbxtext","ebcend","ebcstart","factoidname","falt",
"fchars","ffdeftext","ffentrymcr","ffexitmcr","ffformat","ffhelptext","ffl",
"ffname","ffstattext","field","file","filetbl","fldinst","fldrslt","fldtype",
"fname","fontemb","fontfile","fonttbl","footer","footerf","footerl","footerr",
"footnote","formfield","ftncn","ftnsep","ftnsepc","g","generator","gridtbl",
"header","headerf","headerl","headerr","hl","hlfr","hlinkbase","hlloc","hlsrc",
"hsv","htmltag","info","keycode","keywords","latentstyles","lchars","levelnumbers",
"leveltext","lfolevel","linkval","list","listlevel","listname","listoverride",
"listoverridetable","listpicture","liststylename","listtable","listtext",
"lsdlockedexcept","macc","maccPr","mailmerge","maln","malnScr","manager","margPr",
"mbar","mbarPr","mbaseJc","mbegChr","mborderBox","mborderBoxPr","mbox","mboxPr",
"mchr","mcount","mctrlPr","md","mdeg","mdegHide","mden","mdiff","mdPr","me",
"mendChr","meqArr","meqArrPr","mf","mfName","mfPr","mfunc","mfuncPr","mgroupChr",
"mgroupChrPr","mgrow","mhideBot","mhideLeft","mhideRight","mhideTop","mhtmltag",
"mlim","mlimloc","mlimlow","mlimlowPr","mlimupp","mlimuppPr","mm","mmaddfieldname",
"mmath","mmathPict","mmathPr","mmaxdist","mmc","mmcJc","mmconnectstr",
"mmconnectstrdata","mmcPr","mmcs","mmdatasource","mmheadersource","mmmailsubject",
"mmodso","mmodsofilter","mmodsofldmpdata","mmodsomappedname","mmodsoname",
"mmodsorecipdata","mmodsosort","mmodsosrc","mmodsotable","mmodsoudl",
"mmodsoudldata","mmodsouniquetag","mmPr","mmquery","mmr","mnary","mnaryPr",
"mnoBreak","mnum","mobjDist","moMath","moMathPara","moMathParaPr","mopEmu",
"mphant","mphantPr","mplcHide","mpos","mr","mrad","mradPr","mrPr","msepChr",
"mshow","mshp","msPre","msPrePr","msSub","msSubPr","msSubSup","msSubSupPr","msSup",
"msSupPr","mstrikeBLTR","mstrikeH","mstrikeTLBR","mstrikeV","msub","msubHide",
"msup","msupHide","mtransp","mtype","mvertJc","mvfmf","mvfml","mvtof","mvtol",
"mzeroAsc","mzeroDesc","mzeroWid","nesttableprops","nextfile","nonesttables",
"objalias","objclass","objdata","object","objname","objsect","objtime","oldcprops",
"oldpprops","oldsprops","oldtprops","oleclsid","operator","panose","password",
"passwordhash","pgp","pgptbl","picprop","pict","pn","pnseclvl","pntext","pntxta",
"pntxtb","printim","private","propname","protend","protstart","protusertbl","pxe",
"result","revtbl","revtim","rsidtbl","rxe","shp","shpgrp","shpinst",
"shppict","shprslt","shptxt","sn","sp","staticval","stylesheet","subject","sv",
"svb","tc","template","themedata","title","txe","ud","upr","userprops",
"wgrffmtfilter","windowcaption","writereservation","writereservhash","xe","xform",
"xmlattrname","xmlattrvalue","xmlclose","xmlname","xmlnstbl",
"xmlopen"
};
private static readonly Dictionary<string, string> specialCharacters = new Dictionary<string, string>
{
{ "par", "\n" },
{ "sect", "\n\n" },
{ "page", "\n\n" },
{ "line", "\n" },
{ "tab", "\t" },
{ "emdash", "\u2014" },
{ "endash", "\u2013" },
{ "emspace", "\u2003" },
{ "enspace", "\u2002" },
{ "qmspace", "\u2005" },
{ "bullet", "\u2022" },
{ "lquote", "\u2018" },
{ "rquote", "\u2019" },
{ "ldblquote", "\u201C" },
{ "rdblquote", "\u201D" },
};
/// <summary>
/// Strip RTF Tags from RTF Text
/// </summary>
/// <param name="inputRtf">RTF formatted text</param>
/// <returns>Plain text from RTF</returns>
public static string StripRichTextFormat(string inputRtf)
{
if (inputRtf == null)
{
return null;
}
string returnString;
var stack = new Stack<StackEntry>();
bool ignorable = false; // Whether this group (and all inside it) are "ignorable".
int ucskip = 1; // Number of ASCII characters to skip after a unicode character.
int curskip = 0; // Number of ASCII characters left to skip
var outList = new List<string>(); // Output buffer.
MatchCollection matches = _rtfRegex.Matches(inputRtf);
if (matches.Count > 0)
{
foreach (Match match in matches)
{
string word = match.Groups[1].Value;
string arg = match.Groups[2].Value;
string hex = match.Groups[3].Value;
string character = match.Groups[4].Value;
string brace = match.Groups[5].Value;
string tchar = match.Groups[6].Value;
if (!String.IsNullOrEmpty(brace))
{
curskip = 0;
if (brace == "{")
{
// Push state
stack.Push(new StackEntry(ucskip, ignorable));
}
else if (brace == "}")
{
// Pop state
StackEntry entry = stack.Pop();
ucskip = entry.NumberOfCharactersToSkip;
ignorable = entry.Ignorable;
}
}
else if (!String.IsNullOrEmpty(character)) // \x (not a letter)
{
curskip = 0;
if (character == "~")
{
if (!ignorable)
{
outList.Add("\xA0");
}
}
else if ("{}\\".Contains(character))
{
if (!ignorable)
{
outList.Add(character);
}
}
else if (character == "*")
{
ignorable = true;
}
}
else if (!String.IsNullOrEmpty(word)) // \foo
{
curskip = 0;
if (destinations.Contains(word))
{
ignorable = true;
}
else if (ignorable)
{
}
else if (specialCharacters.ContainsKey(word))
{
outList.Add(specialCharacters[word]);
}
else if (word == "uc")
{
ucskip = Int32.Parse(arg);
}
else if (word == "u")
{
int c = Int32.Parse(arg);
if (c < 0)
{
c += 0x10000;
}
outList.Add(Char.ConvertFromUtf32(c));
curskip = ucskip;
}
}
else if (!String.IsNullOrEmpty(hex)) // \'xx
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
int c = Int32.Parse(hex, System.Globalization.NumberStyles.HexNumber);
outList.Add(Char.ConvertFromUtf32(c));
}
}
else if (!String.IsNullOrEmpty(tchar))
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
outList.Add(tchar);
}
}
}
}
else
{
// Didn't match the regex
returnString = inputRtf;
}
returnString = String.Join(String.Empty, outList.ToArray());
return returnString;
}
}
EDIT 1: In the meantime we had this code running for tests and adapted version in production. The new version does some additional safety checks & handles new lines better.
public static string StripRichTextFormat(string inputRtf)
{
if (inputRtf == null)
{
return null;
}
string returnString;
var stack = new Stack<StackEntry>();
bool ignorable = false; // Whether this group (and all inside it) are "ignorable".
int ucskip = 1; // Number of ASCII characters to skip after a unicode character.
int curskip = 0; // Number of ASCII characters left to skip
var outList = new List<string>(); // Output buffer.
MatchCollection matches = _rtfRegex.Matches(inputRtf);
if (matches.Count > 0)
{
foreach (Match match in matches)
{
string word = match.Groups[1].Value;
string arg = match.Groups[2].Value;
string hex = match.Groups[3].Value;
string character = match.Groups[4].Value;
string brace = match.Groups[5].Value;
string tchar = match.Groups[6].Value;
if (!String.IsNullOrEmpty(brace))
{
curskip = 0;
if (brace == "{")
{
// Push state
stack.Push(new StackEntry(ucskip, ignorable));
}
else if (brace == "}")
{
// Pop state
StackEntry entry = stack.Pop();
ucskip = entry.NumberOfCharactersToSkip;
ignorable = entry.Ignorable;
}
}
else if (!String.IsNullOrEmpty(character)) // \x (not a letter)
{
curskip = 0;
if (character == "~")
{
if (!ignorable)
{
outList.Add("\xA0");
}
}
else if ("{}\\".Contains(character))
{
if (!ignorable)
{
outList.Add(character);
}
}
else if (character == "*")
{
ignorable = true;
}
}
else if (!String.IsNullOrEmpty(word)) // \foo
{
curskip = 0;
if (destinations.Contains(word))
{
ignorable = true;
}
else if (ignorable)
{
}
else if (specialCharacters.ContainsKey(word))
{
outList.Add(specialCharacters[word]);
}
else if (word == "uc")
{
ucskip = Int32.Parse(arg);
}
else if (word == "u")
{
int c = Int32.Parse(arg);
if (c < 0)
{
c += 0x10000;
}
//Ein gültiger UTF32-Wert ist zwischen 0x000000 und 0x10ffff (einschließlich) und sollte keine Ersatzcodepunktwerte (0x00d800 ~ 0x00dfff)
if (c >= 0x000000 && c <= 0x10ffff && (c < 0x00d800 || c > 0x00dfff))
outList.Add(Char.ConvertFromUtf32(c));
else outList.Add("?");
curskip = ucskip;
}
}
else if (!String.IsNullOrEmpty(hex)) // \'xx
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
int c = Int32.Parse(hex, System.Globalization.NumberStyles.HexNumber);
outList.Add(Char.ConvertFromUtf32(c));
}
}
else if (!String.IsNullOrEmpty(tchar))
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
outList.Add(tchar);
}
}
}
}
else
{
// Didn't match the regex
returnString = inputRtf;
}
returnString = String.Join(String.Empty, outList.ToArray());
return returnString;
}
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