Convert HTML to XHTML Online or in C#
Parse HTML and serialize its DOM with XML-compatible XHTML syntax
Download from NuGetProgrammatic HTML to XHTML Conversion for .NET
Aspose.HTML for .NET serializes parsed HTML documents as XHTML inside C# applications. Load a file, URL, string, stream, or HTMLDocument , create HTMLSaveOptions , and use the corresponding save workflow.
Unlike PDF or image conversion, HTML to XHTML is DOM serialization rather than visual rendering.
C# Code Example and Interactive HTML to XHTML Converter
Use the interactive example below to convert an HTML file or URL to XHTML and review the corresponding C# code. Use the generated code as a starting point, then add the settings required by your application.
using Aspose.Html;
using Aspose.Html.Converters;
using Aspose.Html.Saving;
using HTMLDocument document = new HTMLDocument("{{input lower}}");
{{#if_output 'PDF'}}
PdfSaveOptions options = new PdfSaveOptions();
{{/if_output}}
{{#if_output 'MHTML'}}
MHTMLSaveOptions options = new MHTMLSaveOptions();
{{/if_output}}
{{#if_output 'DOCX'}}
DocSaveOptions options = new DocSaveOptions();
{{/if_output}}
{{#if_output 'XPS'}}
XpsSaveOptions options = new XpsSaveOptions();
{{/if_output}}
{{#if_output 'MD'}}
MarkdownSaveOptions options = new MarkdownSaveOptions();
{{/if_output}}
{{#if_output 'BMP' 'JPG' 'GIF' 'PNG' 'TIFF'}}
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.{{output param2 camel}});
{{/if_output}}
{{#if_output 'BMP' 'JPG' 'GIF' 'PNG' 'TIFF' 'PDF' 'MHTML' 'MD' 'XPS' 'DOCX'}}
Converter.ConvertHTML(document, options, "output.{{output lower}}");
{{/if_output}}
{{#if_output 'XHTML'}}
document.Save("output.xhtml", new HTMLSaveOptions() { DocumentType = HTMLSaveOptions.XHTML });
{{/if_output}}
How to Convert HTML to XHTML in C#
- Load the source with an HTMLDocument constructor.
- Create
HTMLSaveOptionsand configure the required output settings. - Set
DocumentTypetoHTMLSaveOptions.XHTMLand callHTMLDocument.Save(). - Validate the generated XHTML with representative source documents.
HTML to XHTML Conversion Options and Documentation
Read the
HTML to XHTML documentation
and consult the HTMLSaveOptions reference for available settings.
Use
HTMLSaveOptions
with DocumentType set to HTMLSaveOptions.XHTML, then call HTMLDocument.Save(). This serializes the DOM as XHTML rather than rendering it to a fixed-layout format.
HTML to XHTML Conversion Notes
- XHTML follows XML rules. Its serialization is stricter than ordinary HTML.
- Parsing can normalize markup. The DOM may differ from the original source text before serialization.
- Runtime state is not captured. Scripts are not executed into static XHTML content.
- Downstream requirements vary. Validate namespaces and XML constraints with representative documents.
- Resources remain references. Embed or rewrite URLs separately when self-contained output is required.
Install Aspose.HTML for .NET
Add the package to your project, then use the C# example above as the minimal HTML to XHTML workflow.
Install Aspose.HTML for .NET from NuGet with the .NET CLI:
dotnet add package Aspose.HTML
You can also use the NuGet Package Manager UI or run Install-Package Aspose.HTML in the Package Manager Console. See the
installation guide
for setup details, or request a
temporary license
to evaluate the API without evaluation limitations.
HTML to XHTML Conversion FAQ
1. How do I convert HTML to XHTML in C#?
Load an HTMLDocument, create HTMLSaveOptions with DocumentType set to HTMLSaveOptions.XHTML, and call HTMLDocument.Save().
2. Is HTML to XHTML a rendering conversion?
No. The API parses HTML and serializes the DOM using XHTML-compatible syntax.
3. Does conversion make invalid HTML well-formed?
The HTML parser builds and normalizes a DOM, which is then serialized as XHTML. Validate the result against any schema required downstream.
4. Are CSS and images embedded in XHTML?
Not automatically. Resource references remain in the serialized document unless the application rewrites or embeds them.
5. Can I convert an HTML string to XHTML?
Yes. Create an HTMLDocument from the markup with an appropriate base URI, then save it with XHTML document type.
Other Supported HTML Conversions
Explore other HTML conversion APIs and C# examples: