只是有关HtmlAgilityPack的注释，以供后代使用。该项目包含一个将文本解析为html的示例，正如OP所指出的那样，它根本不像任何编写HTML的人那样处理空格。有人提供了全文渲染解决方案，对此问题的其他人指出，这不是（它甚至无法处理当前形式的表），但是它是轻量级且快速的，这是我创建简单文本所需的全部HTML电子邮件的版本。
using System.IO;
using System.Text.RegularExpressions;
using HtmlAgilityPack;
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:
break;
case HtmlNodeType.Document:
ConvertContentTo(node, outText, textInfo);
break;
case HtmlNodeType.Text:
string parentName = node.ParentNode.Name;
if ((parentName == "script") || (parentName == "style"))
{
break;
}
html = ((HtmlTextNode)node).Text;
if (HtmlNode.IsOverlappedClosingElement(html))
{
break;
}
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":
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");
}
isInline = false;
break;
case "ol":
listIndex = 1;
goto case "ul";
case "ul":
endElementString = "\r\n";
isInline = false;
break;
case "img":
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 };
}
}
例如，以下HTML代码...
<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<header>
Whatever Inc.
</header>
<main>
<p>
Thanks for your enquiry. As this is the 1<sup>st</sup> time you have contacted us, we would like to clarify a few things:
</p>
<ol>
<li>
Please confirm this is your email by replying.
</li>
<li>
Then perform this step.
</li>
</ol>
<p>
Please solve this <img alt="complex equation" src="http://upload.wikimedia.org/wikipedia/commons/8/8d/First_Equation_Ever.png"/>. Then, in any order, could you please:
</p>
<ul>
<li>
a point.
</li>
<li>
another point, with a <a href="http://en.wikipedia.org/wiki/Hyperlink">hyperlink</a>.
</li>
</ul>
<p>
Sincerely,
</p>
<p>
The whatever.com team
</p>
</main>
<footer>
Ph: 000 000 000<br/>
mail: whatever st
</footer>
</body>
</html>
...将转换为：
Whatever Inc.
Thanks for your enquiry. As this is the 1st time you have contacted us, we would like to clarify a few things:
1. Please confirm this is your email by replying.
2. Then perform this step.
Please solve this [complex equation<http:
* a point.
* another point, with a hyperlink<http:
Sincerely,
The whatever.com team
Ph: 000 000 000
mail: whatever st
...相对于：
Whatever Inc.
Thanks for your enquiry. As this is the 1st time you have contacted us, we would like to clarify a few things:
Please confirm this is your email by replying.
Then perform this step.
Please solve this . Then, in any order, could you please:
a point.
another point, with a hyperlink.
Sincerely,
The whatever.com team
Ph: 000 000 000
mail: whatever st