Aspose.Words XLSX File Processor for .NET

The Aspose.Words XLSX File Processor for .NET lets you create, open, modify, and save XLSX workbooks entirely in managed code. Built on a streamlined subset of the Aspose.Cells engine and designed to integrate with the Aspose.Words conversion pipeline, it provides high‑performance Excel generation/editing for server apps, desktop tools, and cloud services—without Office automation.

Focused on XLSX: worksheets, cells, styles, formulas, charts, data import/export, validation, and protection.

Installation and Setup

  1. Install the NuGet package Aspose.Words (and the XLSX File Processor plugin package, if distributed separately).
  2. Apply your license at application startup to remove evaluation limits: see Metered Licensing .
  3. For framework targets and deployment guidance, see Installation .

This plugin uses a trimmed Excel engine internally and does not require Microsoft Excel.

Supported Platforms: Windows, Linux, macOS (.NET Framework, .NET Core, .NET 5/6+, Mono). Runtime: x64/x86; server and desktop environments.

Quick Start: Create and Save an XLSX 

using Aspose.Cells; // Engine behind the plugin

// 1) Create a workbook with one worksheet
var wb = new Workbook();
Worksheet sheet = wb.Worksheets[0];
sheet.Name = "Report";

// 2) Populate header + data
sheet.Cells["A1"].PutValue("Product");
sheet.Cells["B1"].PutValue("Qty");
sheet.Cells["C1"].PutValue("Price");
sheet.Cells["D1"].PutValue("Total");

sheet.Cells["A2"].PutValue("Keyboard");
sheet.Cells["B2"].PutValue(12);
sheet.Cells["C2"].PutValue(39.99);
sheet.Cells["D2"].Formula = "=B2*C2";

// 3) Style header
var style = wb.CreateStyle();
style.Font.IsBold = true;
style.ForegroundColor = System.Drawing.Color.AliceBlue;
style.Pattern = BackgroundType.Solid;
var flags = new StyleFlag { FontBold = true, CellShading = true };
sheet.Cells.CreateRange("A1", "D1").ApplyStyle(style, flags);

// 4) Auto-fit and save
sheet.AutoFitColumns();
wb.Save("Report.xlsx", SaveFormat.Xlsx);

Load, Edit, and Recalculate 

using Aspose.Cells;

var load = new LoadOptions(LoadFormat.Xlsx);
using var fs = File.OpenRead("Input.xlsx");
var wb = new Workbook(fs, load);

// Update a value and a formula
Worksheet ws = wb.Worksheets["Summary"] ?? wb.Worksheets[0];
ws.Cells["B5"].PutValue(1250);            // new revenue
ws.Cells["B6"].Formula = "=B5*0.18";     // tax 18%

// Calculate formulas only for this sheet to save time
var calcOpts = new CalculationOptions { CalcStackSize = 2000 };
wb.CalculateFormula(calcOpts);

wb.Save("Updated.xlsx", SaveFormat.Xlsx);

Import Data (DataTable → Worksheet) 

using System.Data;
using Aspose.Cells;

DataTable dt = GetData(); // your source
var wb = new Workbook();
var ws = wb.Worksheets[0];

ws.Cells.ImportDataTable(dt, isFieldNameShown: true, firstRow: 0, firstColumn: 0, insertRows: true);
ws.AutoFitColumns();

wb.Save("DataImport.xlsx", SaveFormat.Xlsx);

Insert a Chart (Bound to Data) 

var wb = new Workbook();
var ws = wb.Worksheets[0];

// Sample data
ws.Cells["A1"].PutValue("Month");
ws.Cells["B1"].PutValue("Sales");
string[] months = {"Jan","Feb","Mar","Apr"};
int[] sales = {120, 150, 170, 190};
for (int i = 0; i < months.Length; i++) { ws.Cells[i+1,0].PutValue(months[i]); ws.Cells[i+1,1].PutValue(sales[i]); }

// Add chart
int idx = ws.Charts.Add(ChartType.Column, 6, 0, 20, 8);
Chart chart = ws.Charts[idx];
chart.Title.Text = "Monthly Sales";
chart.NSeries.Add("B2:B5", true);
chart.NSeries.CategoryData = "A2:A5";

wb.Save("Chart.xlsx", SaveFormat.Xlsx);

Add Data Validation & Protect a Sheet 

var wb = new Workbook();
var ws = wb.Worksheets[0];

// Allow only whole numbers between 1 and 100 in B2:B100
Validation v = ws.Validations[ws.Validations.Add()];
v.Type = ValidationType.WholeNumber;
v.Operator = OperatorType.Between;
v.Formula1 = "1";
v.Formula2 = "100";
CellArea area = CellArea.CreateCellArea("B2", "B100");
v.AddArea(area);

// Protect sheet but allow editing unlocked cells
ws.Protection = new Protection { AllowEditingContent = true };
wb.Save("Validated.xlsx", SaveFormat.Xlsx);

Features and Functionality

Workbook Creation & Loading

  • New workbooks with default sheets and styles.
  • Load XLSX from file/stream/byte[] with robust error reporting.
  • Detect password‑protected packages and invalid structures.

Worksheet Management

  • Add/clone/delete/move worksheets; hide/unhide tabs.
  • Address by index or name.

Cells & Ranges

  • Read/write strings, numbers, dates, booleans.
  • Bulk operations over ranges for high throughput.
  • Sparse data supported without bloating file size.

Styling & Formatting

  • Number formats and custom date/time masks.
  • Fonts, fills, borders; named styles for reuse.
  • Conditional formatting rules.

Formulas & Recalculation

  • All common Excel functions (SUM, AVERAGE, VLOOKUP, IF, etc.).
  • Sheet‑scoped or full‑workbook recalculation for performance.
  • Access cached and freshly calculated values.

Charts & Graphics

  • Column/Bar/Line/Pie/Area/Scatter charts.
  • Configure titles, axes, legends, series styles.
  • Insert images (PNG/JPEG/BMP) with position and size control.

Data Import/Export

  • Import from DataTable, arrays, or IEnumerable<T>.
  • Export ranges back to DataTable/collections.
  • Save CSV for lightweight data exchange.

Validation & Protection

  • List/number/date/custom validation rules.
  • Worksheet protection with selective locks and password.

Performance & Memory

  • Streamed writes, batched updates, predictable memory.
  • Manual calc mode during bulk operations.
  • Dispose promptly (use using) to free resources.

Tips & Best Practices

  • Batch writes to contiguous ranges; avoid cell‑by‑cell loops when possible.
  • Reuse named styles to reduce style duplication overhead.
  • Set calculation mode to Manual during large imports, recalc once at the end.
  • Validate inputs before writing to avoid exceptions.
  • Compress large images before insertion to keep files lean.
  • Close/dispose workbooks to flush and free resources.
  • When you only need values, prefer cached results to skip recalculation.

FAQ

Do I need Excel installed? No. The engine is fully managed and headless.

Which formats can I read/write? This processor focuses on XLSX. For broader Excel formats (XLS, ODS) use the full Aspose.Cells product.

Can I calculate formulas server‑side? Yes. Use Workbook.CalculateFormula with options for performance.

What are the Excel limits? XLSX supports up to 1,048,576 rows × 16,384 columns per worksheet.

How does this relate to Aspose.Words? It integrates into Words‑centric pipelines (e.g., convert Word→XLSX or attach XLSX outputs) while relying on a trimmed Excel engine internally.