OfficeIMO.Excel.Html 3.2.4

OfficeIMO.Excel.Html

First-party HTML adapter for OfficeIMO.Excel. It exports semantic worksheet tables or visual review HTML using the shared OfficeIMO.Html profile contracts and the existing Excel SVG image exporter.

Semantic round trips

using OfficeIMO.Excel;
using OfficeIMO.Html;
using OfficeIMO.Excel.Html;

using ExcelDocument workbook = ExcelDocument.Load("report.xlsx", readOnly: true);
string html = workbook.ToHtml(new ExcelHtmlSaveOptions {
    HeaderMode = ExcelHtmlHeaderMode.FirstRow
});

HtmlConversionDocument source = HtmlConversionDocument.Parse(html);
HtmlToExcelResult result = source.ToExcelDocumentResult();
using ExcelDocument imported = result.RequireValue();
imported.Save("report-roundtrip.xlsx");

Semantic output carries a versioned OfficeIMO envelope and preserves worksheet names and visibility, used-range coordinates, typed text/number/boolean/date-time values, formulas, comments, merged ranges, embedded image inventory, supported chart inventory, and inert pivot-definition review metadata. HTML rowspan and colspan values become native Excel merged ranges. Pivot refresh, drill, caches, slicers, and timelines remain native workbook behavior and are not executed in HTML.

HeaderMode makes the first-row assumption explicit. FirstRow is the compatibility default and emits a real thead with column headers. Use None when every row is data.

ToExcelDocument() is the convenience API. It throws HtmlConversionException when no semantic section.officeimo-sheet envelope exists. Use ToExcelDocumentResult() to receive the workbook plus structured diagnostics and loss classification. Export callers can use ToHtmlResult() for the same evidence shape; pivot simplification, truncation, unavailable chart or image content, and visual-renderer fallbacks are operation-scoped diagnostics rather than HTML-only prose.

Ordinary HTML tables are available explicitly through the shared generic projector:

HtmlToExcelResult result = HtmlConversionDocument.Parse(html)
    .ToExcelDocumentResult(new HtmlToExcelOptions {
        Mode = HtmlImportMode.Auto
    });

Semantic remains the default for strict round-trip compatibility. Auto selects a supported semantic envelope when present and otherwise maps ordinary tables to worksheets; Generic always uses the ordinary HTML path. HtmlToExcelOptions.Limits bounds worksheets, tables, cells, images, chart dimensions, metadata, and geometry before native allocations. MaxTableCells remains as a forwarding compatibility property.

SaveAsHtml and SaveAsHtmlAsync write UTF-8 without a byte-order mark to paths or caller-owned streams. For import I/O, use HtmlConversionDocument.Load(...) or LoadAsync(...), then call ToExcelDocument() or ToExcelDocumentResult() on the prepared document. Stream overloads leave caller-owned streams open.

Visual review

Use ExcelHtmlSaveOptions.CreateVisualReviewProfile() or set ExportProfile = ExcelHtmlExportProfile.VisualReview to emit review HTML through OfficeIMO's dependency-free SVG renderer. SharedProfile exposes the corresponding generic engine lane. DocumentOutput controls full-document versus fragment output, title, language, theme, default styles, and newlines. Visual-review HTML is presentation evidence; use semantic tables when the HTML must be imported back into Excel.

Targets

netstandard2.0, net8.0, and net10.0; net472 is included when building on Windows.

Dependency footprint

• External: None beyond the dependencies of its OfficeIMO format packages.
• OfficeIMO: OfficeIMO.Excel, OfficeIMO.Html, and OfficeIMO.Core own the workbook, HTML source, mapping, visual review, and reports.

See the complete OfficeIMO package map for related formats and conversion paths.