devexpress-office-file-api-excel-export

Use the DevExpress Excel Export Library, which streams rows sequentially to an output stream instead of loading the workbook into RAM. Create an exporter with XlExport.CreateExporter, then write sheets, rows, and cells inside nested using blocks.

The Excel Export Library is a forward-only streaming API with very low memory use that cannot read or modify files. The Spreadsheet Document API loads the entire workbook into memory and supports reading, modifying, charts, and pivot tables.

Install the DevExpress.Document.Processor NuGet package for .NET 6/7/8+ projects. For .NET Framework 4.6.2+, reference DevExpress.Printing.v25.2.Core.dll and related assemblies, or use the same NuGet package.

String formulas like cell.SetFormula("=SUM(A1:A5)") require an XlFormulaParser passed to XlExport.CreateExporter. Without it, use expression objects such as XlFunc.Sum and XlOper.Multiply, which need no parser.

No, the Excel Export Library only writes new files in a forward-only streaming manner and cannot read or modify existing documents. For reading or editing files, use the DevExpress Spreadsheet Document API instead.

The file is finalized only when IXlDocument is disposed. Wrap the exporter, document, sheet, row, and cell objects in nested using blocks so each level is disposed in the correct order before the file is flushed.