How to convert Xlsx to SpreadsheetML

Sheetize XLSX‑to‑SpreadsheetML Converter for .NET provides a straightforward API that transforms modern XLSX spreadsheets into the XML‑based SpreadsheetML representation used by older Office versions and many XML‑centric tools. Whether you need to feed data into an XSLT pipeline, generate reports for legacy systems, or simply archive spreadsheets as plain XML, Sheetize handles the conversion with low memory overhead and full fidelity of styles, formulas, and metadata.

Main Features

Convert XLSX to SpreadsheetML

Export a workbook to the standardized SpreadsheetML schema (Office Open XML Spreadsheet) with options for namespace customization, pretty‑printed output, and selective sheet inclusion.

Preserve Formatting & Formulas

All cell styles, merged regions, and formula definitions are retained in the resulting XML, ensuring the output can be re‑opened by Excel or processed by XML tools without loss.

Streaming Support

Process large workbooks in a streaming fashion to keep memory usage minimal – ideal for server‑side batch jobs or cloud functions.

Detailed Instructions

XLSX → SpreadsheetML Workflow

  1. Create the Converter: Instantiate SpreadsheetConverter.
  2. Configure Options: Use SpreadsheetSaveOptions to set the target namespace, indentation, and whether to include hidden worksheets.
  3. Specify Paths: Provide the source .xlsx file and the destination .xml (or .spreadsheetml) file path.
  4. Execute Conversion: Call Process with the load and save options. Example – Convert an XLSX workbook to pretty‑printed SpreadsheetML
using Sheetize;

var loadOptions = new LoadOptions
{
    InputFile = @\"D:\\Data\\report.xlsx\"
};

var saveOptions = new SpreadsheetSaveOptions
{
    OutputFile = @\"D:\\Data\\report.xml\"
};

SpreadsheetConverter.Process(loadOptions, saveOptions);

Expanded Format Support

  • The library can also convert SpreadsheetML back to XLSX, enabling round‑trip transformations.
  • Additional exporters are available for CSV, TSV, and JSON, allowing you to build end‑to‑end pipelines such as XLSX → SpreadsheetML → XSLT → HTML. With Sheetize, turning modern Excel files into the classic XML format is a breeze, whether you need a one‑off script or a production‑grade service.
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