C# FlowDocument to HTML conversion
Basically, I have a RichTextBox and I wa开发者_高级运维nt to convert the formatted contents of it to HTML so it can be sent as an email.
The method I am currently using does not give any formatting at all:
string message = new TextRange(messageTextBox.Document.ContentStart,
messageTextBox.Document.ContentEnd).Text;
So I searched around and found this, however, it is over 5 years old and in the comments an MSFT user has commented saying that it is no longer supported - "This sample has been removed from our sample set and is no longer supported"
, and the HTML it generates is in an older format than modern HTML or XHTML which would be better to have.
Can anybody show me how I can convert the formatted contents of a RichTextBox to HTML?
(So when the email is sent it the recipient sees the email with formatting)
The general technique is to use a XamlWriter
to convert the FlowDocument
content to a stream of XML, and then to use an XSLT transform to convert the XML to HTML. That's not much of an answer, but that's because there's a huge range of possible HTML representations of any given FlowDocument.
This transform, for instance, converts every top-level Section
to a div
, every Paragraph
to a p
, and every Run
to a span
whose class tells you whether or not it's italicized, bold-faced, or underlined, or any combination of the above. It was useful for the purpose I wrote it for, but to call it a lossy transformation is an understatement:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
exclude-result-prefixes="msxsl x">
<xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>
<xsl:template match="x:Section[not(parent::x:Section)]">
<div>
<xsl:apply-templates select="node()"/>
</div>
</xsl:template>
<xsl:template match="x:Section">
<xsl:apply-templates select="node()"/>
</xsl:template>
<xsl:template match="x:Paragraph">
<p>
<xsl:apply-templates select="node()"/>
</p>
</xsl:template>
<xsl:template match="x:Run">
<xsl:variable name="class">
<xsl:if test="@FontStyle='Italic'">
<xsl:text>i </xsl:text>
</xsl:if>
<xsl:if test="@FontWeight='Bold'">
<xsl:text>b </xsl:text>
</xsl:if>
<xsl:if test="contains(@TextDecorations, 'Underline')">
<xsl:text>u </xsl:text>
</xsl:if>
</xsl:variable>
<span>
<xsl:if test="normalize-space($class) != ''">
<xsl:attribute name="class">
<xsl:value-of select="normalize-space($class)"/>
</xsl:attribute>
</xsl:if>
<xsl:value-of select="text()"/>
</span>
</xsl:template>
</xsl:stylesheet>
Here's a value converter I wrote to do the conversion - note that in order to use the value converter, you also have to hack around and implement a version of RichTextBox
that exposes the content as a dependency property. Really this whole project was a pain.
public class FlowDocumentToHtmlConverter : IValueConverter
{
private static XslCompiledTransform ToHtmlTransform;
private static XslCompiledTransform ToXamlTransform;
public FlowDocumentToHtmlConverter()
{
if (ToHtmlTransform == null)
{
ToHtmlTransform = LoadTransformResource("Converters/FlowDocumentToXhtml.xslt");
}
if (ToXamlTransform == null)
{
ToXamlTransform = LoadTransformResource("Converters/XhtmlToFlowDocument.xslt");
}
}
private static XslCompiledTransform LoadTransformResource(string path)
{
Uri uri = new Uri(path, UriKind.Relative);
XmlReader xr = XmlReader.Create(Application.GetResourceStream(uri).Stream);
XslCompiledTransform xslt = new XslCompiledTransform();
xslt.Load(xr);
return xslt;
}
#region IValueConverter Members
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (!(value is FlowDocument))
{
return null;
}
if (targetType == typeof(FlowDocument))
{
return value;
}
if (targetType != typeof(string))
{
throw new InvalidOperationException(
"FlowDocumentToHtmlConverter can only convert back from a FlowDocument to a string.");
}
FlowDocument d = (FlowDocument)value;
using (MemoryStream ms = new MemoryStream())
{
// write XAML out to a MemoryStream
TextRange tr = new TextRange(
d.ContentStart,
d.ContentEnd);
tr.Save(ms, DataFormats.Xaml);
ms.Seek(0, SeekOrigin.Begin);
// transform the contents of the MemoryStream to HTML
StringBuilder sb = new StringBuilder();
using (StringWriter sw = new StringWriter(sb))
{
XmlWriterSettings xws = new XmlWriterSettings();
xws.OmitXmlDeclaration = true;
XmlReader xr = XmlReader.Create(ms);
XmlWriter xw = XmlWriter.Create(sw, xws);
ToHtmlTransform.Transform(xr, xw);
}
return sb.ToString();
}
}
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value == null)
{
return new FlowDocument();
}
if (value is FlowDocument)
{
return value;
}
if (targetType != typeof(FlowDocument))
{
throw new InvalidOperationException(
"FlowDocumentToHtmlConverter can only convert to a FlowDocument.");
}
if (!(value is string))
{
throw new InvalidOperationException(
"FlowDocumentToHtmlConverter can only convert from a string or FlowDocument.");
}
string s = (string)value;
FlowDocument d;
using (MemoryStream ms = new MemoryStream())
using (StringReader sr = new StringReader(s))
{
XmlWriterSettings xws = new XmlWriterSettings();
xws.OmitXmlDeclaration = true;
using (XmlReader xr = XmlReader.Create(sr))
using (XmlWriter xw = XmlWriter.Create(ms, xws))
{
ToXamlTransform.Transform(xr, xw);
}
ms.Seek(0, SeekOrigin.Begin);
d = XamlReader.Load(ms) as FlowDocument;
}
XamlWriter.Save(d, Console.Out);
return d;
}
#endregion
}
Extended version of XSLT sheet above I thought might help. Not perfect but slightly more comprehensive. Extension of an extension of another answer referencing this one.
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
exclude-result-prefixes="msxsl x">
<xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>
<!--<xsl:template match="x:Section[not(parent::x:Section)]">
<div>
<xsl:apply-templates select="node()"/>
</div>
</xsl:template>-->
<xsl:template match="x:Section[not(parent::x:Section)]">
<xsl:variable name="style">
<xsl:if test="@FontStyle='Italic'">
<xsl:text>font-style:italic;</xsl:text>
</xsl:if>
<xsl:if test="@FontWeight='Bold'">
<xsl:text>font-weight:bold;</xsl:text>
</xsl:if>
<xsl:if test="contains(@TextDecorations, 'Underline')">
<xsl:text>text-decoration:underline;</xsl:text>
</xsl:if>
<xsl:if test="@FontSize != ''">
<xsl:text>font-size:</xsl:text>
<xsl:value-of select="@FontSize" />
<xsl:text>pt;</xsl:text>
</xsl:if>
<xsl:if test="@FontFamily != ''">
<xsl:text>font-family:</xsl:text>
<xsl:value-of select="@FontFamily" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="concat(substring(@Foreground, 1, 1), substring(@Foreground, 4))" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground-Color != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="@Foreground-Color"/>
<xsl:text>;</xsl:text>
</xsl:if>
</xsl:variable>
<div>
<xsl:if test="normalize-space($style) != ''">
<xsl:attribute name="style">
<xsl:value-of select="normalize-space($style)"/>
</xsl:attribute>
</xsl:if>
<xsl:value-of select="text()"/>
<xsl:apply-templates select="node()"/>
</div>
</xsl:template>
<xsl:template match="x:Section">
<xsl:apply-templates select="node()"/>
</xsl:template>
<xsl:template match="x:Paragraph">
<xsl:variable name="style">
<xsl:if test="@FontStyle='Italic'">
<xsl:text>font-style:italic;</xsl:text>
</xsl:if>
<xsl:if test="@FontWeight='Bold'">
<xsl:text>font-weight:bold;</xsl:text>
</xsl:if>
<xsl:if test="contains(@TextDecorations, 'Underline')">
<xsl:text>text-decoration:underline;</xsl:text>
</xsl:if>
<xsl:if test="@FontSize != ''">
<xsl:text>font-size:</xsl:text>
<xsl:value-of select="@FontSize" />
<xsl:text>pt;</xsl:text>
</xsl:if>
<xsl:if test="@FontFamily != ''">
<xsl:text>font-family:</xsl:text>
<xsl:value-of select="@FontFamily" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="concat(substring(@Foreground, 1, 1), substring(@Foreground, 4))" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground-Color != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="@Foreground-Color"/>
<xsl:text>;</xsl:text>
</xsl:if>
</xsl:variable>
<p>
<xsl:if test="normalize-space($style) != ''">
<xsl:attribute name="style">
<xsl:value-of select="normalize-space($style)"/>
</xsl:attribute>
</xsl:if>
<xsl:value-of select="text()"/>
<xsl:apply-templates select="node()"/>
</p>
</xsl:template>
<xsl:template match="x:Span">
<xsl:variable name="style">
<xsl:if test="@FontStyle='Italic'">
<xsl:text>font-style:italic;</xsl:text>
</xsl:if>
<xsl:if test="@FontWeight='Bold'">
<xsl:text>font-weight:bold;</xsl:text>
</xsl:if>
<xsl:if test="contains(@TextDecorations, 'Underline')">
<xsl:text>text-decoration:underline;</xsl:text>
</xsl:if>
<xsl:if test="@FontSize != ''">
<xsl:text>font-size:</xsl:text>
<xsl:value-of select="@FontSize" />
<xsl:text>pt;</xsl:text>
</xsl:if>
<xsl:if test="@FontFamily != ''">
<xsl:text>font-family:</xsl:text>
<xsl:value-of select="@FontFamily" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="concat(substring(@Foreground, 1, 1), substring(@Foreground, 4))" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground-Color != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="@Foreground-Color"/>
<xsl:text>;</xsl:text>
</xsl:if>
</xsl:variable>
<span>
<xsl:if test="normalize-space($style) != ''">
<xsl:attribute name="style">
<xsl:value-of select="normalize-space($style)"/>
</xsl:attribute>
</xsl:if>
<xsl:value-of select="text()"/>
<xsl:apply-templates select="node()"/>
</span>
</xsl:template>
<xsl:template match="x:Run">
<xsl:variable name="style">
<xsl:if test="@FontStyle='Italic'">
<xsl:text>font-style:italic;</xsl:text>
</xsl:if>
<xsl:if test="@FontWeight='Bold'">
<xsl:text>font-weight:bold;</xsl:text>
</xsl:if>
<xsl:if test="contains(@TextDecorations, 'Underline')">
<xsl:text>text-decoration:underline;</xsl:text>
</xsl:if>
<xsl:if test="@FontSize != ''">
<xsl:text>font-size:</xsl:text>
<xsl:value-of select="@FontSize" />
<xsl:text>pt;</xsl:text>
</xsl:if>
<xsl:if test="@FontFamily != ''">
<xsl:text>font-family:</xsl:text>
<xsl:value-of select="@FontFamily" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="concat(substring(@Foreground, 1, 1), substring(@Foreground, 4))" />
<xsl:text>;</xsl:text>
</xsl:if>
<xsl:if test="@Foreground-Color != ''">
<xsl:text>color:</xsl:text>
<xsl:value-of select="@Foreground-Color"/>
<xsl:text>;</xsl:text>
</xsl:if>
</xsl:variable>
<span>
<xsl:if test="normalize-space($style) != ''">
<xsl:attribute name="style">
<xsl:value-of select="normalize-space($style)"/>
</xsl:attribute>
</xsl:if>
<xsl:value-of select="text()"/>
<xsl:apply-templates select="node()"/>
</span>
</xsl:template>
</xsl:stylesheet>
For those who is looking for solution for .Net Core (APS.Net Core) - nuget MarkupConverter did the trick for me. Add dependency reference
<PackageReference Include="MarkupConverter" Version="1.0.6" />
Then use it
MarkupConverter.MarkupConverter markupConverter = new MarkupConverter.MarkupConverter();
try
{
message = markupConverter.ConvertXamlToHtml(message);
}
catch (Exception ex)
{
_logger.LogError(ex, $"Failed to parse flowdocument");
}
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