FormulaEngineer — A Highly Accurate Excel Formula Engine with support for 430+ Excel functions — explore the complete list NEW3.0.1

FormulaEngineer examples

Create, read, and style Excel workbooks in .NET.

Style workbooks as you write them — fonts, fills, borders, number formats, alignment, and layout — using ExcelStyledWriter. Every example below is a complete, runnable snippet.

Group
Example
10 examples in Layout

Streaming auto-fit columns

Turns on auto-fit for columns whose content length varies widely. Widths are estimated from the values as they stream past, with the supplied width acting as a minimum floor.

Write.cs
using FormulaEngineer.Api;
using FormulaEngineer.Api.Styling;

var headerStyle =
    ExcelStyle.Default.With(
        font: ExcelFontStyle.Bold,
        fill: ExcelFillStyle.Solid(
            ExcelColor.FromRgb(221, 235, 247)));

using (var writer = new ExcelStyledWriter("streaming-autofit-columns.xlsx"))
{
    using (var sheet = writer.CreateWorksheet("AutoFit"))
    {
        sheet.SetColumnStyle(1, ExcelColumnStyle.Default.With(width: 10d));
        sheet.SetColumnStyle(2, ExcelColumnStyle.Default.With(width: 12d, autoFit: true));
        sheet.SetColumnStyle(3, ExcelColumnStyle.Default.With(width: 14d, autoFit: true));

        sheet.WriteRow(
            new object?[] { "ID", "Customer", "Status note" },
            headerStyle);

        sheet.WriteRow("C-100", "Northwind Finance", "Ready for review");
        sheet.WriteRow("C-200", "Contoso International Holdings", "Generated from a streamed export without loading the workbook into memory");
        sheet.WriteRow("C-300", "Fabrikam", "Approved");
    }

    writer.Close();
}

Style your own workbooks

Styling is part of the same package — no separate install, no Excel, no COM automation.