Cellwright.Formulas 0.1.2

Cellwright

A modern .NET 10 Excel library, layered like System.Text.Json: primitives → constant-memory streaming → mutable DOM → source-generated typed mapping. Data-oriented cell storage — column slices in 512-row pages, not an object per cell. Async-first I/O, zero reflection, Native AOT and trimming safe. Apache-2.0 licensed.

using Cellwright;

// Read
Workbook book = await Workbook.LoadAsync("report.xlsx");
Worksheet sheet = book.Sheets[0];
CellValue total = sheet["B10"];

// Edit
sheet["C2"] = 1234.5;
sheet.Cell("C2").SetStyle(CellStyle.Default.Bold().NumberFormat("#,##0.00"));
sheet.Cell("C3").SetFormula("SUM(C1:C2)");

// Write
await book.SaveAsync("report.xlsx");

What the core package covers

• Constant-memory streaming: forward-only XlsxWriter (UTF-8 straight to the wire) and XlsxReader (IAsyncEnumerable<RowData>) for files of any size.
• A full worksheet model: values, styles, formulas (round-tripped as text), merged cells, freeze panes, hidden rows and columns, grouping, auto-filter, hyperlinks, notes and threaded comments, Excel tables, data validation, conditional formatting, page setup, protection, document properties, rich text runs, embedded charts (read and create), pictures.
• Lossless editing of foreign files: pivot tables, themes, macros and anything else the model does not represent travels through byte for byte; renaming a sheet retargets formulas, defined names and chart references.
• Styles per ISO/IEC 29500 §18.8: immutable records with free interning, fluent builders, pattern and gradient fills, theme colors, cell protection.
• Recovery-oriented loading: recoverable problems become coded WorkbookWarnings instead of exceptions, and hostile input (zip bombs, wrong formats) is named rather than crashed on.
• Markdown export: book.ToMarkdown() renders sheets as GitHub Flavored Markdown tables.

The Cellwright family

Documentation

Guides, per-feature docs and the full list of deliberate limitations live in the repository: https://github.com/WrightDocumentSuite/cellwright

Every deviation from the spec is documented and reported through diagnostics — nothing is silently dropped or approximated without saying so.