I have snippets of Html stored in a table. Not entire pages, no tags or the like, just basic formatting.
I would like to be able to display that Html as text only, no formatting, on a given page (actually just the first 30 - 50 characters but that's the easy bit).
How do I place the "text" within that Html into a string as straight text?
So this piece of code.
<b>Hello World.</b><br/><p><i>Is there anyone out there?</i><p>
Becomes:
Hello World. Is there anyone out there?
I think it has a simple answer:
public string RemoveHTMLTags(string HTMLCode)
{
string str=System.Text.RegularExpressions.Regex.Replace(HTMLCode, "<[^>]*>", "");
return str;
}
It has limitation that not collapsing long inline whitespace, but it is definitely portable and respects layout like webbrowser.
static string HtmlToPlainText(string html) {
string buf;
string block = "address|article|aside|blockquote|canvas|dd|div|dl|dt|" +
"fieldset|figcaption|figure|footer|form|h\\d|header|hr|li|main|nav|" +
"noscript|ol|output|p|pre|section|table|tfoot|ul|video";
string patNestedBlock = $"(\\s*?</?({block})[^>]*?>)+\\s*";
buf = Regex.Replace(html, patNestedBlock, "\n", RegexOptions.IgnoreCase);
// Replace br tag to newline.
buf = Regex.Replace(buf, @"<(br)[^>]*>", "\n", RegexOptions.IgnoreCase);
// (Optional) remove styles and scripts.
buf = Regex.Replace(buf, @"<(script|style)[^>]*?>.*?</\1>", "", RegexOptions.Singleline);
// Remove all tags.
buf = Regex.Replace(buf, @"<[^>]*(>|$)", "", RegexOptions.Multiline);
// Replace HTML entities.
buf = WebUtility.HtmlDecode(buf);
return buf;
}
HTTPUtility.HTMLEncode() is meant to handle encoding HTML tags as strings. It takes care of all the heavy lifting for you. From the MSDN Documentation:
If characters such as blanks and punctuation are passed in an HTTP stream, they might be misinterpreted at the receiving end. HTML encoding converts characters that are not allowed in HTML into character-entity equivalents; HTML decoding reverses the encoding. For example, when embedded in a block of text, the characters
<and>, are encoded as<and>for HTTP transmission.
HTTPUtility.HTMLEncode() method, detailed here:
public static void HtmlEncode(
string s,
TextWriter output
)
Usage:
String TestString = "This is a <Test String>.";
StringWriter writer = new StringWriter();
Server.HtmlEncode(TestString, writer);
String EncodedString = writer.ToString();
There not a method with the name 'ConvertToPlainText' in the HtmlAgilityPack but you can convert a html string to CLEAR string with :
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(htmlString);
var textString = doc.DocumentNode.InnerText;
Regex.Replace(textString , @"<(.|n)*?>", string.Empty).Replace(" ", "");
Thats works for me. BUT I DONT FIND A METHOD WITH NAME 'ConvertToPlainText' IN 'HtmlAgilityPack'.
The simplest way I found:
HtmlFilter.ConvertToPlainText(html);
The HtmlFilter class is located in Microsoft.TeamFoundation.WorkItemTracking.Controls.dll
The dll can be found in folder like this: %ProgramFiles%\Common Files\microsoft shared\Team Foundation Server\14.0\
In VS 2015, the dll also requires reference to Microsoft.TeamFoundation.WorkItemTracking.Common.dll, located in the same folder.
To add to vfilby's answer, you can just perform a RegEx replace within your code; no new classes are necessary. In case other newbies like myself stumple upon this question.
using System.Text.RegularExpressions;
Then...
private string StripHtml(string source)
{
string output;
//get rid of HTML tags
output = Regex.Replace(source, "<[^>]*>", string.Empty);
//get rid of multiple blank lines
output = Regex.Replace(output, @"^\s*$\n", string.Empty, RegexOptions.Multiline);
return output;
}
public static string StripTags2(string html) { return html.Replace("<", "<").Replace(">", ">"); }
By this you escape all "<" and ">" in a string. Is this what you want?
If you have data that has HTML tags and you want to display it so that a person can SEE the tags, use HttpServerUtility::HtmlEncode.
If you have data that has HTML tags in it and you want the user to see the tags rendered, then display the text as is. If the text represents an entire web page, use an IFRAME for it.
If you have data that has HTML tags and you want to strip out the tags and just display the unformatted text, use a regular expression.
Depends on what you mean by "html." The most complex case would be complete web pages. That's also the easiest to handle, since you can use a text-mode web browser. See the Wikipedia article listing web browsers, including text mode browsers. Lynx is probably the best known, but one of the others may be better for your needs.
public static string StripTags2(string html) { return html.Replace("<", "<").Replace(">", ">"); }
By this you escape all "<" and ">" in a string. Is this what you want?
The MIT licensed HtmlAgilityPack has in one of its samples a method that converts from HTML to plain text.
var plainText = HtmlUtilities.ConvertToPlainText(string html);
Feed it an HTML string like
<b>hello, <i>world!</i></b>
And you'll get a plain text result like:
hello world!
public static string StripTags2(string html) { return html.Replace("<", "<").Replace(">", ">"); }
By this you escape all "<" and ">" in a string. Is this what you want?
Here is my solution:
public string StripHTML(string html)
{
if (string.IsNullOrWhiteSpace(html)) return "";
// could be stored in static variable
var regex = new Regex("<[^>]+>|\\s{2}", RegexOptions.IgnoreCase);
return System.Web.HttpUtility.HtmlDecode(regex.Replace(html, ""));
}
Example:
StripHTML("<p class='test' style='color:red;'>Here is my solution:</p>");
// output -> Here is my solution:
HTTPUtility.HTMLEncode() is meant to handle encoding HTML tags as strings. It takes care of all the heavy lifting for you. From the MSDN Documentation:
If characters such as blanks and punctuation are passed in an HTTP stream, they might be misinterpreted at the receiving end. HTML encoding converts characters that are not allowed in HTML into character-entity equivalents; HTML decoding reverses the encoding. For example, when embedded in a block of text, the characters
<and>, are encoded as<and>for HTTP transmission.
HTTPUtility.HTMLEncode() method, detailed here:
public static void HtmlEncode(
string s,
TextWriter output
)
Usage:
String TestString = "This is a <Test String>.";
StringWriter writer = new StringWriter();
Server.HtmlEncode(TestString, writer);
String EncodedString = writer.ToString();
Here is my solution:
public string StripHTML(string html)
{
if (string.IsNullOrWhiteSpace(html)) return "";
// could be stored in static variable
var regex = new Regex("<[^>]+>|\\s{2}", RegexOptions.IgnoreCase);
return System.Web.HttpUtility.HtmlDecode(regex.Replace(html, ""));
}
Example:
StripHTML("<p class='test' style='color:red;'>Here is my solution:</p>");
// output -> Here is my solution:
Did not write but an using:
using HtmlAgilityPack;
using System;
using System.IO;
using System.Text.RegularExpressions;
namespace foo {
//small but important modification to class https://github.com/zzzprojects/html-agility-pack/blob/master/src/Samples/Html2Txt/HtmlConvert.cs
public static class HtmlToText {
public static string Convert(string path) {
HtmlDocument doc = new HtmlDocument();
doc.Load(path);
return ConvertDoc(doc);
}
public static string ConvertHtml(string html) {
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(html);
return ConvertDoc(doc);
}
public static string ConvertDoc(HtmlDocument doc) {
using (StringWriter sw = new StringWriter()) {
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
}
internal static void ConvertContentTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo) {
foreach (HtmlNode subnode in node.ChildNodes) {
ConvertTo(subnode, outText, textInfo);
}
}
public static void ConvertTo(HtmlNode node, TextWriter outText) {
ConvertTo(node, outText, new PreceedingDomTextInfo(false));
}
internal static void ConvertTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo) {
string html;
switch (node.NodeType) {
case HtmlNodeType.Comment:
// don't output comments
break;
case HtmlNodeType.Document:
ConvertContentTo(node, outText, textInfo);
break;
case HtmlNodeType.Text:
// script and style must not be output
string parentName = node.ParentNode.Name;
if ((parentName == "script") || (parentName == "style")) {
break;
}
// get text
html = ((HtmlTextNode)node).Text;
// is it in fact a special closing node output as text?
if (HtmlNode.IsOverlappedClosingElement(html)) {
break;
}
// check the text is meaningful and not a bunch of whitespaces
if (html.Length == 0) {
break;
}
if (!textInfo.WritePrecedingWhiteSpace || textInfo.LastCharWasSpace) {
html = html.TrimStart();
if (html.Length == 0) { break; }
textInfo.IsFirstTextOfDocWritten.Value = textInfo.WritePrecedingWhiteSpace = true;
}
outText.Write(HtmlEntity.DeEntitize(Regex.Replace(html.TrimEnd(), @"\s{2,}", " ")));
if (textInfo.LastCharWasSpace = char.IsWhiteSpace(html[html.Length - 1])) {
outText.Write(' ');
}
break;
case HtmlNodeType.Element:
string endElementString = null;
bool isInline;
bool skip = false;
int listIndex = 0;
switch (node.Name) {
case "nav":
skip = true;
isInline = false;
break;
case "body":
case "section":
case "article":
case "aside":
case "h1":
case "h2":
case "header":
case "footer":
case "address":
case "main":
case "div":
case "p": // stylistic - adjust as you tend to use
if (textInfo.IsFirstTextOfDocWritten) {
outText.Write("\r\n");
}
endElementString = "\r\n";
isInline = false;
break;
case "br":
outText.Write("\r\n");
skip = true;
textInfo.WritePrecedingWhiteSpace = false;
isInline = true;
break;
case "a":
if (node.Attributes.Contains("href")) {
string href = node.Attributes["href"].Value.Trim();
if (node.InnerText.IndexOf(href, StringComparison.InvariantCultureIgnoreCase) == -1) {
endElementString = "<" + href + ">";
}
}
isInline = true;
break;
case "li":
if (textInfo.ListIndex > 0) {
outText.Write("\r\n{0}.\t", textInfo.ListIndex++);
} else {
outText.Write("\r\n*\t"); //using '*' as bullet char, with tab after, but whatever you want eg "\t->", if utf-8 0x2022
}
isInline = false;
break;
case "ol":
listIndex = 1;
goto case "ul";
case "ul": //not handling nested lists any differently at this stage - that is getting close to rendering problems
endElementString = "\r\n";
isInline = false;
break;
case "img": //inline-block in reality
if (node.Attributes.Contains("alt")) {
outText.Write('[' + node.Attributes["alt"].Value);
endElementString = "]";
}
if (node.Attributes.Contains("src")) {
outText.Write('<' + node.Attributes["src"].Value + '>');
}
isInline = true;
break;
default:
isInline = true;
break;
}
if (!skip && node.HasChildNodes) {
ConvertContentTo(node, outText, isInline ? textInfo : new PreceedingDomTextInfo(textInfo.IsFirstTextOfDocWritten) { ListIndex = listIndex });
}
if (endElementString != null) {
outText.Write(endElementString);
}
break;
}
}
}
internal class PreceedingDomTextInfo {
public PreceedingDomTextInfo(BoolWrapper isFirstTextOfDocWritten) {
IsFirstTextOfDocWritten = isFirstTextOfDocWritten;
}
public bool WritePrecedingWhiteSpace { get; set; }
public bool LastCharWasSpace { get; set; }
public readonly BoolWrapper IsFirstTextOfDocWritten;
public int ListIndex { get; set; }
}
internal class BoolWrapper {
public BoolWrapper() { }
public bool Value { get; set; }
public static implicit operator bool(BoolWrapper boolWrapper) {
return boolWrapper.Value;
}
public static implicit operator BoolWrapper(bool boolWrapper) {
return new BoolWrapper { Value = boolWrapper };
}
}
}
There not a method with the name 'ConvertToPlainText' in the HtmlAgilityPack but you can convert a html string to CLEAR string with :
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(htmlString);
var textString = doc.DocumentNode.InnerText;
Regex.Replace(textString , @"<(.|n)*?>", string.Empty).Replace(" ", "");
Thats works for me. BUT I DONT FIND A METHOD WITH NAME 'ConvertToPlainText' IN 'HtmlAgilityPack'.
public static string StripTags2(string html) { return html.Replace("<", "<").Replace(">", ">"); }
By this you escape all "<" and ">" in a string. Is this what you want?
I had the same question, just my html had a simple pre-known layout, like:
<DIV><P>abc</P><P>def</P></DIV>
So I ended up using such simple code:
string.Join (Environment.NewLine, XDocument.Parse (html).Root.Elements ().Select (el => el.Value))
Which outputs:
abc
def
Did not write but an using:
using HtmlAgilityPack;
using System;
using System.IO;
using System.Text.RegularExpressions;
namespace foo {
//small but important modification to class https://github.com/zzzprojects/html-agility-pack/blob/master/src/Samples/Html2Txt/HtmlConvert.cs
public static class HtmlToText {
public static string Convert(string path) {
HtmlDocument doc = new HtmlDocument();
doc.Load(path);
return ConvertDoc(doc);
}
public static string ConvertHtml(string html) {
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(html);
return ConvertDoc(doc);
}
public static string ConvertDoc(HtmlDocument doc) {
using (StringWriter sw = new StringWriter()) {
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
}
internal static void ConvertContentTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo) {
foreach (HtmlNode subnode in node.ChildNodes) {
ConvertTo(subnode, outText, textInfo);
}
}
public static void ConvertTo(HtmlNode node, TextWriter outText) {
ConvertTo(node, outText, new PreceedingDomTextInfo(false));
}
internal static void ConvertTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo) {
string html;
switch (node.NodeType) {
case HtmlNodeType.Comment:
// don't output comments
break;
case HtmlNodeType.Document:
ConvertContentTo(node, outText, textInfo);
break;
case HtmlNodeType.Text:
// script and style must not be output
string parentName = node.ParentNode.Name;
if ((parentName == "script") || (parentName == "style")) {
break;
}
// get text
html = ((HtmlTextNode)node).Text;
// is it in fact a special closing node output as text?
if (HtmlNode.IsOverlappedClosingElement(html)) {
break;
}
// check the text is meaningful and not a bunch of whitespaces
if (html.Length == 0) {
break;
}
if (!textInfo.WritePrecedingWhiteSpace || textInfo.LastCharWasSpace) {
html = html.TrimStart();
if (html.Length == 0) { break; }
textInfo.IsFirstTextOfDocWritten.Value = textInfo.WritePrecedingWhiteSpace = true;
}
outText.Write(HtmlEntity.DeEntitize(Regex.Replace(html.TrimEnd(), @"\s{2,}", " ")));
if (textInfo.LastCharWasSpace = char.IsWhiteSpace(html[html.Length - 1])) {
outText.Write(' ');
}
break;
case HtmlNodeType.Element:
string endElementString = null;
bool isInline;
bool skip = false;
int listIndex = 0;
switch (node.Name) {
case "nav":
skip = true;
isInline = false;
break;
case "body":
case "section":
case "article":
case "aside":
case "h1":
case "h2":
case "header":
case "footer":
case "address":
case "main":
case "div":
case "p": // stylistic - adjust as you tend to use
if (textInfo.IsFirstTextOfDocWritten) {
outText.Write("\r\n");
}
endElementString = "\r\n";
isInline = false;
break;
case "br":
outText.Write("\r\n");
skip = true;
textInfo.WritePrecedingWhiteSpace = false;
isInline = true;
break;
case "a":
if (node.Attributes.Contains("href")) {
string href = node.Attributes["href"].Value.Trim();
if (node.InnerText.IndexOf(href, StringComparison.InvariantCultureIgnoreCase) == -1) {
endElementString = "<" + href + ">";
}
}
isInline = true;
break;
case "li":
if (textInfo.ListIndex > 0) {
outText.Write("\r\n{0}.\t", textInfo.ListIndex++);
} else {
outText.Write("\r\n*\t"); //using '*' as bullet char, with tab after, but whatever you want eg "\t->", if utf-8 0x2022
}
isInline = false;
break;
case "ol":
listIndex = 1;
goto case "ul";
case "ul": //not handling nested lists any differently at this stage - that is getting close to rendering problems
endElementString = "\r\n";
isInline = false;
break;
case "img": //inline-block in reality
if (node.Attributes.Contains("alt")) {
outText.Write('[' + node.Attributes["alt"].Value);
endElementString = "]";
}
if (node.Attributes.Contains("src")) {
outText.Write('<' + node.Attributes["src"].Value + '>');
}
isInline = true;
break;
default:
isInline = true;
break;
}
if (!skip && node.HasChildNodes) {
ConvertContentTo(node, outText, isInline ? textInfo : new PreceedingDomTextInfo(textInfo.IsFirstTextOfDocWritten) { ListIndex = listIndex });
}
if (endElementString != null) {
outText.Write(endElementString);
}
break;
}
}
}
internal class PreceedingDomTextInfo {
public PreceedingDomTextInfo(BoolWrapper isFirstTextOfDocWritten) {
IsFirstTextOfDocWritten = isFirstTextOfDocWritten;
}
public bool WritePrecedingWhiteSpace { get; set; }
public bool LastCharWasSpace { get; set; }
public readonly BoolWrapper IsFirstTextOfDocWritten;
public int ListIndex { get; set; }
}
internal class BoolWrapper {
public BoolWrapper() { }
public bool Value { get; set; }
public static implicit operator bool(BoolWrapper boolWrapper) {
return boolWrapper.Value;
}
public static implicit operator BoolWrapper(bool boolWrapper) {
return new BoolWrapper { Value = boolWrapper };
}
}
}
I think the easiest way is to make a 'string' extension method (based on what user Richard have suggested):
using System;
using System.Text.RegularExpressions;
public static class StringHelpers
{
public static string StripHTML(this string HTMLText)
{
var reg = new Regex("<[^>]+>", RegexOptions.IgnoreCase);
return reg.Replace(HTMLText, "");
}
}
Then just use this extension method on any 'string' variable in your program:
var yourHtmlString = "<div class=\"someclass\"><h2>yourHtmlText</h2></span>";
var yourTextString = yourHtmlString.StripHTML();
I use this extension method to convert html formated comments to plain text so it will be displayed correctly on a crystal report, and it works perfect!
I think it has a simple answer:
public string RemoveHTMLTags(string HTMLCode)
{
string str=System.Text.RegularExpressions.Regex.Replace(HTMLCode, "<[^>]*>", "");
return str;
}
Three Step Process for converting HTML into Plain Text
First You need to Install Nuget Package For HtmlAgilityPack Second Create This class
public class HtmlToText
{
public HtmlToText()
{
}
public string Convert(string path)
{
HtmlDocument doc = new HtmlDocument();
doc.Load(path);
StringWriter sw = new StringWriter();
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
public string ConvertHtml(string html)
{
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(html);
StringWriter sw = new StringWriter();
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
private void ConvertContentTo(HtmlNode node, TextWriter outText)
{
foreach(HtmlNode subnode in node.ChildNodes)
{
ConvertTo(subnode, outText);
}
}
public void ConvertTo(HtmlNode node, TextWriter outText)
{
string html;
switch(node.NodeType)
{
case HtmlNodeType.Comment:
// don't output comments
break;
case HtmlNodeType.Document:
ConvertContentTo(node, outText);
break;
case HtmlNodeType.Text:
// script and style must not be output
string parentName = node.ParentNode.Name;
if ((parentName == "script") || (parentName == "style"))
break;
// get text
html = ((HtmlTextNode)node).Text;
// is it in fact a special closing node output as text?
if (HtmlNode.IsOverlappedClosingElement(html))
break;
// check the text is meaningful and not a bunch of whitespaces
if (html.Trim().Length > 0)
{
outText.Write(HtmlEntity.DeEntitize(html));
}
break;
case HtmlNodeType.Element:
switch(node.Name)
{
case "p":
// treat paragraphs as crlf
outText.Write("\r\n");
break;
}
if (node.HasChildNodes)
{
ConvertContentTo(node, outText);
}
break;
}
}
}
By using above class with reference to Judah Himango's answer
Third you need to create the Object of above class and Use ConvertHtml(HTMLContent) Method for converting HTML into Plain Text rather than ConvertToPlainText(string html);
HtmlToText htt=new HtmlToText();
var plainText = htt.ConvertHtml(HTMLContent);
Depends on what you mean by "html." The most complex case would be complete web pages. That's also the easiest to handle, since you can use a text-mode web browser. See the Wikipedia article listing web browsers, including text mode browsers. Lynx is probably the best known, but one of the others may be better for your needs.
For anyone looking for an exact solution to the OP question for a textual abbreviation of a given html document, without newlines and HTML tags, please find the solution below.
Like with every proposed solution, there are some assumptions with the code below:
he<span>ll</span>o should output hello. List of inline
tags: https://www.w3schools.com/htmL/html_blocks.aspConsidering the above, the following string extension with compiled regular expressions will output expected plain text with regard to html escaped characters and null on null input.
public static class StringExtensions
{
public static string ConvertToPlain(this string html)
{
if (html == null)
{
return html;
}
html = scriptRegex.Replace(html, string.Empty);
html = inlineTagRegex.Replace(html, string.Empty);
html = tagRegex.Replace(html, " ");
html = HttpUtility.HtmlDecode(html);
html = multiWhitespaceRegex.Replace(html, " ");
return html.Trim();
}
private static readonly Regex inlineTagRegex = new Regex("<\\/?(a|span|sub|sup|b|i|strong|small|big|em|label|q)[^>]*>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex scriptRegex = new Regex("<(script|style)[^>]*?>.*?</\\1>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex tagRegex = new Regex("<[^>]+>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex multiWhitespaceRegex = new Regex("\\s+", RegexOptions.Compiled | RegexOptions.Singleline);
}
It has limitation that not collapsing long inline whitespace, but it is definitely portable and respects layout like webbrowser.
static string HtmlToPlainText(string html) {
string buf;
string block = "address|article|aside|blockquote|canvas|dd|div|dl|dt|" +
"fieldset|figcaption|figure|footer|form|h\\d|header|hr|li|main|nav|" +
"noscript|ol|output|p|pre|section|table|tfoot|ul|video";
string patNestedBlock = $"(\\s*?</?({block})[^>]*?>)+\\s*";
buf = Regex.Replace(html, patNestedBlock, "\n", RegexOptions.IgnoreCase);
// Replace br tag to newline.
buf = Regex.Replace(buf, @"<(br)[^>]*>", "\n", RegexOptions.IgnoreCase);
// (Optional) remove styles and scripts.
buf = Regex.Replace(buf, @"<(script|style)[^>]*?>.*?</\1>", "", RegexOptions.Singleline);
// Remove all tags.
buf = Regex.Replace(buf, @"<[^>]*(>|$)", "", RegexOptions.Multiline);
// Replace HTML entities.
buf = WebUtility.HtmlDecode(buf);
return buf;
}
HTTPUtility.HTMLEncode() is meant to handle encoding HTML tags as strings. It takes care of all the heavy lifting for you. From the MSDN Documentation:
If characters such as blanks and punctuation are passed in an HTTP stream, they might be misinterpreted at the receiving end. HTML encoding converts characters that are not allowed in HTML into character-entity equivalents; HTML decoding reverses the encoding. For example, when embedded in a block of text, the characters
<and>, are encoded as<and>for HTTP transmission.
HTTPUtility.HTMLEncode() method, detailed here:
public static void HtmlEncode(
string s,
TextWriter output
)
Usage:
String TestString = "This is a <Test String>.";
StringWriter writer = new StringWriter();
Server.HtmlEncode(TestString, writer);
String EncodedString = writer.ToString();
If you have data that has HTML tags and you want to display it so that a person can SEE the tags, use HttpServerUtility::HtmlEncode.
If you have data that has HTML tags in it and you want the user to see the tags rendered, then display the text as is. If the text represents an entire web page, use an IFRAME for it.
If you have data that has HTML tags and you want to strip out the tags and just display the unformatted text, use a regular expression.
I think the easiest way is to make a 'string' extension method (based on what user Richard have suggested):
using System;
using System.Text.RegularExpressions;
public static class StringHelpers
{
public static string StripHTML(this string HTMLText)
{
var reg = new Regex("<[^>]+>", RegexOptions.IgnoreCase);
return reg.Replace(HTMLText, "");
}
}
Then just use this extension method on any 'string' variable in your program:
var yourHtmlString = "<div class=\"someclass\"><h2>yourHtmlText</h2></span>";
var yourTextString = yourHtmlString.StripHTML();
I use this extension method to convert html formated comments to plain text so it will be displayed correctly on a crystal report, and it works perfect!
I have faced similar problem and found best solution . Below code works perfect for me.
private string ConvertHtml_Totext(string source)
{
try
{
string result;
// Remove HTML Development formatting
// Replace line breaks with space
// because browsers inserts space
result = source.Replace("\r", " ");
// Replace line breaks with space
// because browsers inserts space
result = result.Replace("\n", " ");
// Remove step-formatting
result = result.Replace("\t", string.Empty);
// Remove repeating spaces because browsers ignore them
result = System.Text.RegularExpressions.Regex.Replace(result,
@"( )+", " ");
// Remove the header (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*head([^>])*>","<head>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*head( )*>)","</head>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(<head>).*(</head>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// remove all scripts (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*script([^>])*>","<script>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*script( )*>)","</script>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
//result = System.Text.RegularExpressions.Regex.Replace(result,
// @"(<script>)([^(<script>\.</script>)])*(</script>)",
// string.Empty,
// System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<script>).*(</script>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// remove all styles (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*style([^>])*>","<style>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*style( )*>)","</style>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(<style>).*(</style>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert tabs in spaces of <td> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*td([^>])*>","\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert line breaks in places of <BR> and <LI> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*br( )*>","\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*li( )*>","\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert line paragraphs (double line breaks) in place
// if <P>, <DIV> and <TR> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*div([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*tr([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*p([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove remaining tags like <a>, links, images,
// comments etc - anything that's enclosed inside < >
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<[^>]*>",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// replace special characters:
result = System.Text.RegularExpressions.Regex.Replace(result,
@" "," ",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"•"," * ",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"‹","<",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"›",">",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"™","(tm)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"⁄","/",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<","<",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@">",">",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"©","(c)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"®","(r)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove all others. More can be added, see
// http://hotwired.lycos.com/webmonkey/reference/special_characters/
result = System.Text.RegularExpressions.Regex.Replace(result,
@"&(.{2,6});", string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// for testing
//System.Text.RegularExpressions.Regex.Replace(result,
// this.txtRegex.Text,string.Empty,
// System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// make line breaking consistent
result = result.Replace("\n", "\r");
// Remove extra line breaks and tabs:
// replace over 2 breaks with 2 and over 4 tabs with 4.
// Prepare first to remove any whitespaces in between
// the escaped characters and remove redundant tabs in between line breaks
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)( )+(\r)","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\t)( )+(\t)","\t\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\t)( )+(\r)","\t\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)( )+(\t)","\r\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove redundant tabs
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)(\t)+(\r)","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove multiple tabs following a line break with just one tab
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)(\t)+","\r\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Initial replacement target string for line breaks
string breaks = "\r\r\r";
// Initial replacement target string for tabs
string tabs = "\t\t\t\t\t";
for (int index=0; index<result.Length; index++)
{
result = result.Replace(breaks, "\r\r");
result = result.Replace(tabs, "\t\t\t\t");
breaks = breaks + "\r";
tabs = tabs + "\t";
}
// That's it.
return result;
}
catch
{
MessageBox.Show("Error");
return source;
}
}
Escape characters such as \n and \r had to be removed first because they cause regexes to cease working as expected.
Moreover, to make the result string display correctly in the textbox, one might need to split it up and set textbox's Lines property instead of assigning to Text property.
this.txtResult.Lines = StripHTML(this.txtSource.Text).Split("\r".ToCharArray());
Source : https://www.codeproject.com/Articles/11902/Convert-HTML-to-Plain-Text-2
The simplest way I found:
HtmlFilter.ConvertToPlainText(html);
The HtmlFilter class is located in Microsoft.TeamFoundation.WorkItemTracking.Controls.dll
The dll can be found in folder like this: %ProgramFiles%\Common Files\microsoft shared\Team Foundation Server\14.0\
In VS 2015, the dll also requires reference to Microsoft.TeamFoundation.WorkItemTracking.Common.dll, located in the same folder.
The MIT licensed HtmlAgilityPack has in one of its samples a method that converts from HTML to plain text.
var plainText = HtmlUtilities.ConvertToPlainText(string html);
Feed it an HTML string like
<b>hello, <i>world!</i></b>
And you'll get a plain text result like:
hello world!
To add to vfilby's answer, you can just perform a RegEx replace within your code; no new classes are necessary. In case other newbies like myself stumple upon this question.
using System.Text.RegularExpressions;
Then...
private string StripHtml(string source)
{
string output;
//get rid of HTML tags
output = Regex.Replace(source, "<[^>]*>", string.Empty);
//get rid of multiple blank lines
output = Regex.Replace(output, @"^\s*$\n", string.Empty, RegexOptions.Multiline);
return output;
}
I could not use HtmlAgilityPack, so I wrote a second best solution for myself
private static string HtmlToPlainText(string html)
{
const string tagWhiteSpace = @"(>|$)(\W|\n|\r)+<";//matches one or more (white space or line breaks) between '>' and '<'
const string stripFormatting = @"<[^>]*(>|$)";//match any character between '<' and '>', even when end tag is missing
const string lineBreak = @"<(br|BR)\s{0,1}\/{0,1}>";//matches: <br>,<br/>,<br />,<BR>,<BR/>,<BR />
var lineBreakRegex = new Regex(lineBreak, RegexOptions.Multiline);
var stripFormattingRegex = new Regex(stripFormatting, RegexOptions.Multiline);
var tagWhiteSpaceRegex = new Regex(tagWhiteSpace, RegexOptions.Multiline);
var text = html;
//Decode html specific characters
text = System.Net.WebUtility.HtmlDecode(text);
//Remove tag whitespace/line breaks
text = tagWhiteSpaceRegex.Replace(text, "><");
//Replace <br /> with line breaks
text = lineBreakRegex.Replace(text, Environment.NewLine);
//Strip formatting
text = stripFormattingRegex.Replace(text, string.Empty);
return text;
}
I had the same question, just my html had a simple pre-known layout, like:
<DIV><P>abc</P><P>def</P></DIV>
So I ended up using such simple code:
string.Join (Environment.NewLine, XDocument.Parse (html).Root.Elements ().Select (el => el.Value))
Which outputs:
abc
def
Depends on what you mean by "html." The most complex case would be complete web pages. That's also the easiest to handle, since you can use a text-mode web browser. See the Wikipedia article listing web browsers, including text mode browsers. Lynx is probably the best known, but one of the others may be better for your needs.
I have faced similar problem and found best solution . Below code works perfect for me.
private string ConvertHtml_Totext(string source)
{
try
{
string result;
// Remove HTML Development formatting
// Replace line breaks with space
// because browsers inserts space
result = source.Replace("\r", " ");
// Replace line breaks with space
// because browsers inserts space
result = result.Replace("\n", " ");
// Remove step-formatting
result = result.Replace("\t", string.Empty);
// Remove repeating spaces because browsers ignore them
result = System.Text.RegularExpressions.Regex.Replace(result,
@"( )+", " ");
// Remove the header (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*head([^>])*>","<head>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*head( )*>)","</head>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(<head>).*(</head>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// remove all scripts (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*script([^>])*>","<script>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*script( )*>)","</script>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
//result = System.Text.RegularExpressions.Regex.Replace(result,
// @"(<script>)([^(<script>\.</script>)])*(</script>)",
// string.Empty,
// System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<script>).*(</script>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// remove all styles (prepare first by clearing attributes)
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*style([^>])*>","<style>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"(<( )*(/)( )*style( )*>)","</style>",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(<style>).*(</style>)",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert tabs in spaces of <td> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*td([^>])*>","\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert line breaks in places of <BR> and <LI> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*br( )*>","\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*li( )*>","\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// insert line paragraphs (double line breaks) in place
// if <P>, <DIV> and <TR> tags
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*div([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*tr([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<( )*p([^>])*>","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove remaining tags like <a>, links, images,
// comments etc - anything that's enclosed inside < >
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<[^>]*>",string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// replace special characters:
result = System.Text.RegularExpressions.Regex.Replace(result,
@" "," ",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"•"," * ",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"‹","<",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"›",">",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"™","(tm)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"⁄","/",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"<","<",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@">",">",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"©","(c)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
@"®","(r)",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove all others. More can be added, see
// http://hotwired.lycos.com/webmonkey/reference/special_characters/
result = System.Text.RegularExpressions.Regex.Replace(result,
@"&(.{2,6});", string.Empty,
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// for testing
//System.Text.RegularExpressions.Regex.Replace(result,
// this.txtRegex.Text,string.Empty,
// System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// make line breaking consistent
result = result.Replace("\n", "\r");
// Remove extra line breaks and tabs:
// replace over 2 breaks with 2 and over 4 tabs with 4.
// Prepare first to remove any whitespaces in between
// the escaped characters and remove redundant tabs in between line breaks
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)( )+(\r)","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\t)( )+(\t)","\t\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\t)( )+(\r)","\t\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)( )+(\t)","\r\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove redundant tabs
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)(\t)+(\r)","\r\r",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Remove multiple tabs following a line break with just one tab
result = System.Text.RegularExpressions.Regex.Replace(result,
"(\r)(\t)+","\r\t",
System.Text.RegularExpressions.RegexOptions.IgnoreCase);
// Initial replacement target string for line breaks
string breaks = "\r\r\r";
// Initial replacement target string for tabs
string tabs = "\t\t\t\t\t";
for (int index=0; index<result.Length; index++)
{
result = result.Replace(breaks, "\r\r");
result = result.Replace(tabs, "\t\t\t\t");
breaks = breaks + "\r";
tabs = tabs + "\t";
}
// That's it.
return result;
}
catch
{
MessageBox.Show("Error");
return source;
}
}
Escape characters such as \n and \r had to be removed first because they cause regexes to cease working as expected.
Moreover, to make the result string display correctly in the textbox, one might need to split it up and set textbox's Lines property instead of assigning to Text property.
this.txtResult.Lines = StripHTML(this.txtSource.Text).Split("\r".ToCharArray());
Source : https://www.codeproject.com/Articles/11902/Convert-HTML-to-Plain-Text-2
I could not use HtmlAgilityPack, so I wrote a second best solution for myself
private static string HtmlToPlainText(string html)
{
const string tagWhiteSpace = @"(>|$)(\W|\n|\r)+<";//matches one or more (white space or line breaks) between '>' and '<'
const string stripFormatting = @"<[^>]*(>|$)";//match any character between '<' and '>', even when end tag is missing
const string lineBreak = @"<(br|BR)\s{0,1}\/{0,1}>";//matches: <br>,<br/>,<br />,<BR>,<BR/>,<BR />
var lineBreakRegex = new Regex(lineBreak, RegexOptions.Multiline);
var stripFormattingRegex = new Regex(stripFormatting, RegexOptions.Multiline);
var tagWhiteSpaceRegex = new Regex(tagWhiteSpace, RegexOptions.Multiline);
var text = html;
//Decode html specific characters
text = System.Net.WebUtility.HtmlDecode(text);
//Remove tag whitespace/line breaks
text = tagWhiteSpaceRegex.Replace(text, "><");
//Replace <br /> with line breaks
text = lineBreakRegex.Replace(text, Environment.NewLine);
//Strip formatting
text = stripFormattingRegex.Replace(text, string.Empty);
return text;
}
Three Step Process for converting HTML into Plain Text
First You need to Install Nuget Package For HtmlAgilityPack Second Create This class
public class HtmlToText
{
public HtmlToText()
{
}
public string Convert(string path)
{
HtmlDocument doc = new HtmlDocument();
doc.Load(path);
StringWriter sw = new StringWriter();
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
public string ConvertHtml(string html)
{
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(html);
StringWriter sw = new StringWriter();
ConvertTo(doc.DocumentNode, sw);
sw.Flush();
return sw.ToString();
}
private void ConvertContentTo(HtmlNode node, TextWriter outText)
{
foreach(HtmlNode subnode in node.ChildNodes)
{
ConvertTo(subnode, outText);
}
}
public void ConvertTo(HtmlNode node, TextWriter outText)
{
string html;
switch(node.NodeType)
{
case HtmlNodeType.Comment:
// don't output comments
break;
case HtmlNodeType.Document:
ConvertContentTo(node, outText);
break;
case HtmlNodeType.Text:
// script and style must not be output
string parentName = node.ParentNode.Name;
if ((parentName == "script") || (parentName == "style"))
break;
// get text
html = ((HtmlTextNode)node).Text;
// is it in fact a special closing node output as text?
if (HtmlNode.IsOverlappedClosingElement(html))
break;
// check the text is meaningful and not a bunch of whitespaces
if (html.Trim().Length > 0)
{
outText.Write(HtmlEntity.DeEntitize(html));
}
break;
case HtmlNodeType.Element:
switch(node.Name)
{
case "p":
// treat paragraphs as crlf
outText.Write("\r\n");
break;
}
if (node.HasChildNodes)
{
ConvertContentTo(node, outText);
}
break;
}
}
}
By using above class with reference to Judah Himango's answer
Third you need to create the Object of above class and Use ConvertHtml(HTMLContent) Method for converting HTML into Plain Text rather than ConvertToPlainText(string html);
HtmlToText htt=new HtmlToText();
var plainText = htt.ConvertHtml(HTMLContent);
Depends on what you mean by "html." The most complex case would be complete web pages. That's also the easiest to handle, since you can use a text-mode web browser. See the Wikipedia article listing web browsers, including text mode browsers. Lynx is probably the best known, but one of the others may be better for your needs.
HTTPUtility.HTMLEncode() is meant to handle encoding HTML tags as strings. It takes care of all the heavy lifting for you. From the MSDN Documentation:
If characters such as blanks and punctuation are passed in an HTTP stream, they might be misinterpreted at the receiving end. HTML encoding converts characters that are not allowed in HTML into character-entity equivalents; HTML decoding reverses the encoding. For example, when embedded in a block of text, the characters
<and>, are encoded as<and>for HTTP transmission.
HTTPUtility.HTMLEncode() method, detailed here:
public static void HtmlEncode(
string s,
TextWriter output
)
Usage:
String TestString = "This is a <Test String>.";
StringWriter writer = new StringWriter();
Server.HtmlEncode(TestString, writer);
String EncodedString = writer.ToString();
For anyone looking for an exact solution to the OP question for a textual abbreviation of a given html document, without newlines and HTML tags, please find the solution below.
Like with every proposed solution, there are some assumptions with the code below:
he<span>ll</span>o should output hello. List of inline
tags: https://www.w3schools.com/htmL/html_blocks.aspConsidering the above, the following string extension with compiled regular expressions will output expected plain text with regard to html escaped characters and null on null input.
public static class StringExtensions
{
public static string ConvertToPlain(this string html)
{
if (html == null)
{
return html;
}
html = scriptRegex.Replace(html, string.Empty);
html = inlineTagRegex.Replace(html, string.Empty);
html = tagRegex.Replace(html, " ");
html = HttpUtility.HtmlDecode(html);
html = multiWhitespaceRegex.Replace(html, " ");
return html.Trim();
}
private static readonly Regex inlineTagRegex = new Regex("<\\/?(a|span|sub|sup|b|i|strong|small|big|em|label|q)[^>]*>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex scriptRegex = new Regex("<(script|style)[^>]*?>.*?</\\1>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex tagRegex = new Regex("<[^>]+>", RegexOptions.Compiled | RegexOptions.Singleline);
private static readonly Regex multiWhitespaceRegex = new Regex("\\s+", RegexOptions.Compiled | RegexOptions.Singleline);
}
If you have data that has HTML tags and you want to display it so that a person can SEE the tags, use HttpServerUtility::HtmlEncode.
If you have data that has HTML tags in it and you want the user to see the tags rendered, then display the text as is. If the text represents an entire web page, use an IFRAME for it.
If you have data that has HTML tags and you want to strip out the tags and just display the unformatted text, use a regular expression.
Source: Stackoverflow.com