Edit Excel Formulas in C# Using IronXL

Why Is IronXL the Best Choice for Formula Editing?

IronXL eliminates the need for Microsoft Office Interop while providing direct formula access through intuitive properties. The library supports over 165 built-in Excel functions, handles complex formula dependencies automatically, and delivers fast processing across Windows, Linux, and macOS platforms. Its lightweight architecture ensures Excel-compatible calculations without external dependencies.

What Are the System Requirements?

IronXL requires .NET Framework 4.6.2 or higher, or .NET Core 2.0 and above. The library runs on Windows, Linux, and macOS without requiring Microsoft Excel installation. For optimal performance with large workbooks containing complex formulas, we recommend at least 4GB RAM. Check the complete documentation for detailed platform-specific requirements.

How Do I Get Started with IronXL?

Install the NuGet package using Package Manager Console with Install-Package IronXL.Excel. After installation, apply your license key to unlock full functionality. Import the IronXL namespace in your C# file to begin editing formulas. The intuitive API design allows you to load Excel files and modify formulas within minutes.

How Do I Edit Formulas in Excel Using C#?

To edit or set the formula, access the Formula property. First, select a Range or Cell, and then access and set the Formula property. The Formula property is both a get and set property that returns the formula string, if any. Invoke the EvaluateAll method to re-evaluate the entire workbook, ensuring accurate calculations.

:path=/static-assets/excel/content-code-examples/how-to/edit-formulas-edit-formulas.cs

using IronXL;

// Load workbook
WorkBook workBook = WorkBook.Load("Book1.xlsx");

// Select worksheet
WorkSheet workSheet = workBook.DefaultWorkSheet;

// Edit or Set formula
workSheet["A4"].Formula = "=SUM(A1,A3)";

// Reevaluate the entire workbook
workBook.EvaluateAll();

Imports IronXL

' Load workbook
Private workBook As WorkBook = WorkBook.Load("Book1.xlsx")

' Select worksheet
Private workSheet As WorkSheet = workBook.DefaultWorkSheet

' Edit or Set formula
Private workSheet("A4").Formula = "=SUM(A1,A3)"

' Reevaluate the entire workbook
workBook.EvaluateAll()

IronXL provides complete flexibility when working with formulas. You can modify existing formulas, create new ones, or build dynamic formulas based on runtime conditions. The library handles formula syntax validation automatically, ensuring Excel compatibility. For complex scenarios, explore comprehensive formula examples demonstrating advanced manipulation techniques.

How Do I Retrieve Results from Formulas?

To retrieve the result from a formula, use the FormattedCellValue property of the Cell for a precise result. Within a selected Range, access the Cell using the First method, which selects the first element of the sequence. From there, access the FormattedCellValue property.

:path=/static-assets/excel/content-code-examples/how-to/edit-formulas-retrieve-formula-value.cs

using IronXL;
using System;
using System.Linq;

// Load workbook
WorkBook workBook = WorkBook.Load("Book1.xlsx");

// Select worksheet
WorkSheet workSheet = workBook.DefaultWorkSheet;

// Retrieve the result value
string value = workSheet["A4"].First().FormattedCellValue;

// Print the result to console
Console.WriteLine(value);

Imports IronXL
Imports System
Imports System.Linq

' Load workbook
Private workBook As WorkBook = WorkBook.Load("Book1.xlsx")

' Select worksheet
Private workSheet As WorkSheet = workBook.DefaultWorkSheet

' Retrieve the result value
Private value As String = workSheet("A4").First().FormattedCellValue

' Print the result to console
Console.WriteLine(value)

The FormattedCellValue property returns the cell's value as it would appear in Excel, respecting number formats, date formats, and custom formatting rules. This ensures consistency between your programmatic output and what users see in Excel. For numerical analysis, access the raw value through the Value property, which returns the underlying numeric or text data without formatting applied.

Which Excel Formulas Are Supported by IronXL?

Excel contains 450+ formulas for various calculation purposes. IronXL supports around 165 of the most commonly used formulas. Check the following for supported formulas: