FreePPlus.LgplLicenseForever 1.0.252.254

FreePPlus

Create advanced Excel spreadsheets using .NET, without the need of interop.

FreePPlus is a .NET library that reads and writes Excel files using the Office Open XML format (xlsx). FreePPlus is provided as a .NET 10 library and associated FreePPlus.LgplLicenseForever NuGet package.

FreePPlus supports applications and assemblies that target Microsoft .NET version 10.0 and later. Microsoft .NET version 10.0 is a Long-Term Supported (LTS) version of .NET, and was released on Nov 11, 2025; and will be actively supported by Microsoft until Nov 14, 2028. Please update your C#/.NET code and projects to the latest LTS version of Microsoft .NET.

Installation

dotnet add package FreePPlus.LgplLicenseForever

The NuGet package ID and the namespace are completely different names here, and it is the easiest thing about this package to get wrong. There is no package named OfficeOpenXml, and using FreePPlus; resolves to nothing:

• NuGet package ID: FreePPlus.LgplLicenseForever
• Assembly: FreePPlus.OfficeOpenXml
• Primary namespace: OfficeOpenXml - i.e. using OfficeOpenXml;, with OfficeOpenXml.Style, OfficeOpenXml.Table and the other sub-namespaces beneath it

XML documentation (IntelliSense) ships alongside the assembly.

The package pulls in the following automatically; no version pinning is needed in the consuming project:

• CodeBrix.Imaging.ApacheLicenseForever - image and font handling
• Microsoft.Extensions.Configuration, Microsoft.Extensions.Configuration.FileExtensions and Microsoft.Extensions.Configuration.Json
• System.Security.Cryptography.Pkcs

FreePPlus supports:

• Cell Ranges
• Cell styling (Border, Color, Fill, Font, Number, Alignments)
• Data validation
• Conditional formatting
• Charts
• Pictures
• Shapes
• Comments
• Tables
• Pivot tables
• Protection
• Encryption
• VBA
• Formula calculation
• Many more...

Sample Code

Create a New Excel File

using OfficeOpenXml;
using OfficeOpenXml.Style;

// Create a new workbook and add a worksheet
using var package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("Sales Report");

// Add headers
ws.Cells["A1"].Value = "Product";
ws.Cells["B1"].Value = "Quantity";
ws.Cells["C1"].Value = "Unit Price";
ws.Cells["D1"].Value = "Total";

// Add data
ws.Cells["A2"].Value = "Widget";
ws.Cells["B2"].Value = 25;
ws.Cells["C2"].Value = 3.50;

ws.Cells["A3"].Value = "Gadget";
ws.Cells["B3"].Value = 10;
ws.Cells["C3"].Value = 12.99;

ws.Cells["A4"].Value = "Gizmo";
ws.Cells["B4"].Value = 50;
ws.Cells["C4"].Value = 1.75;

// Add formulas
ws.Cells["D2:D4"].Formula = "B2*C2";

// Style the header row
using (var range = ws.Cells["A1:D1"])
{
    range.Style.Font.Bold = true;
    range.Style.Fill.PatternType = ExcelFillStyle.Solid;
    range.Style.Fill.BackgroundColor.SetColor(0, 0, 51, 102);    // dark blue
    range.Style.Font.Color.SetColor(255, 255, 255, 255);         // white
}

// Format currency columns
ws.Cells["C2:D4"].Style.Numberformat.Format = "#,##0.00";

// Auto-fit column widths
ws.Cells["A1:D4"].AutoFitColumns();

// Save to a file
package.SaveAs(new FileInfo("SalesReport.xlsx"));

Open and Read an Existing File

using OfficeOpenXml;

using var package = new ExcelPackage(new FileInfo("SalesReport.xlsx"));
var ws = package.Workbook.Worksheets["Sales Report"];

// Read cell values
for (int row = 2; row <= 4; row++)
{
    var product = ws.Cells[row, 1].Text;
    var quantity = ws.Cells[row, 2].GetValue<int>();
    Console.WriteLine($"{product}: {quantity} units");
}

Load Data from a Collection

using OfficeOpenXml;
using OfficeOpenXml.Table;

var inventory = new[]
{
    new { Sku = "A100", Name = "Hammer", Stock = 37, Price = 12.10m },
    new { Sku = "A101", Name = "Nails",  Stock = 500, Price = 3.99m },
    new { Sku = "A102", Name = "Saw",    Stock = 12, Price = 15.37m },
};

using var package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("Inventory");

// Load collection with headers and a table style
ws.Cells["A1"].LoadFromCollection(inventory, true, TableStyles.Medium6);
ws.Cells["A1:D1"].AutoFitColumns();

package.SaveAs(new FileInfo("Inventory.xlsx"));

Add Formulas and Calculate

using OfficeOpenXml;

using var package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("Calculations");

ws.Cells["A1"].Value = 100;
ws.Cells["A2"].Value = 200;
ws.Cells["A3"].Value = 300;
ws.Cells["A4"].Formula = "SUM(A1:A3)";
ws.Cells["A5"].Formula = "AVERAGE(A1:A3)";

// Calculate formulas in memory
ws.Calculate();

Console.WriteLine($"Sum:     {ws.Cells["A4"].Value}");   // 600
Console.WriteLine($"Average: {ws.Cells["A5"].Value}");   // 200

package.SaveAs(new FileInfo("Calculations.xlsx"));

Protect a Worksheet and Workbook

using OfficeOpenXml;

using var package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("Protected");

ws.Cells["A1"].Value = "This sheet is protected";

// Protect the worksheet (uses SHA-512 hashing)
ws.Protection.SetPassword("sheetPass");
ws.Protection.AllowSelectLockedCells = true;
ws.Protection.AllowSelectUnlockedCells = true;

// Protect the workbook structure
package.Workbook.Protection.SetPassword("workbookPass");
package.Workbook.Protection.LockStructure = true;

package.SaveAs(new FileInfo("Protected.xlsx"));

Save with Encryption

using OfficeOpenXml;

using var package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("Encrypted");
ws.Cells["A1"].Value = "Sensitive data";

// Save with a file-open password (AES encryption)
package.SaveAs(new FileInfo("Encrypted.xlsx"), "openPassword");

Documentation

The NuGet package includes AGENT-README.txt, a complete API reference and usage guide written for AI coding agents - point your agent at that file when it is writing code against this library.

Additional sample code and usage examples are available in the FreePPlus.OfficeOpenXml.Tests project: https://github.com/ellisnet/FreePPlus/tree/main/tests/FreePPlus.OfficeOpenXml.Tests

A console application that walks through a set of worked scenarios is in the FreePPlus.OfficeOpenXml.SampleApp project: https://github.com/ellisnet/FreePPlus/tree/main/samples/FreePPlus.OfficeOpenXml.SampleApp

License

FreePPlus is licensed under the GNU Lesser General Public License (LGPL) version 3 - see the LICENSE file. All modified, adapted and derived code in this library is made freely available as open source under that same license.

For licensing and provenance information about the open source code included in this package, see THIRD-PARTY-NOTICES.txt.