ExcelHelperEx 1.1.6

ExcelHelperEx

Simple extension methods to save and load lists of POCOs to and from Excel (.xlsx) and CSV files using EPPlus.

Install

Add the NuGet package to your project.

Features

• Save a List<T> to .xlsx or .csv
• Read a .xlsx sheet or .csv into List<T>
• Maps headers to properties via DisplayNameAttribute (preferred) or property name
• Case-insensitive header matching, ignores spaces and non-alphanumeric characters
• Supports: string, int, double, decimal, bool, DateTime, DateTime?

Quick start

using System;
using System.Collections.Generic;
using System.ComponentModel;
using ExcelHelperEx;

public class Person
{
    [DisplayName("First Name")] public string FirstName { get; set; }
    [DisplayName("Last Name")] public string LastName { get; set; }
    public int Age { get; set; }
    public DateTime? BirthDate { get; set; }
}

var people = new List<Person>
{
    new Person { FirstName = "Ada", LastName = "Lovelace", Age = 36, BirthDate = new DateTime(1815, 12, 10) },
    new Person { FirstName = "Alan", LastName = "Turing", Age = 41, BirthDate = new DateTime(1912, 6, 23) }
};

// Write
people.SaveToExcel("people.xlsx");
people.SaveToCsv("people.csv");

// Or choose based on extension
people.SaveToExcelOrCsv("people.xlsx");
people.SaveToExcelOrCsv("people.csv");

// Read (Excel)
var fromExcel = "people.xlsx".ReadFromExcel<Person>();

// Read (CSV)
var fromCsv = "people.csv".ReadFromCsv<Person>();

// Read choosing by extension
var auto = "people.xlsx".ReadFromExcelOrCsv<Person>();

Read a specific worksheet

You can target a worksheet by its name or by its zero-based index. If both are provided, the name takes precedence.

// By sheet name
var byName = "people.xlsx".ReadFromExcel<Person>(sheetName: "Employees");

// By sheet index (zero-based)
var byIndex = "people.xlsx".ReadFromExcel<Person>(sheetIndex: 1); // reads the 2nd sheet

// Choosing by extension with sheet selection
var autoByName = "people.xlsx".ReadFromExcelOrCsv<Person>(sheetName: "Employees");
var autoByIndex = "people.xlsx".ReadFromExcelOrCsv<Person>(sheetIndex: 1);

Excel specifics

• The first row is treated as headers and is matched to properties via:
  1. DisplayNameAttribute on the property, or 2) property name (split into words)
• A worksheet named data is created when writing
• Date/time cells are formatted as MM/dd/yyyy HH:mm:ss
• An Excel table style (Medium2) is applied and columns are auto-sized

CSV specifics

• The first line is treated as the header
• DateTime values are formatted using the general ("G") pattern when writing

Header mapping rules

• Matching is case-insensitive
• Spaces and non-alphanumeric characters are ignored
• Examples: "First Name", "First-Name", "firstname" all map to property FirstName

Type support

• string, int, double, decimal, bool, DateTime, DateTime?
• Excel numeric dates (OADate) are converted to DateTime when reading

Error handling

• Writing overwrites existing target files
• Reading throws when the source file is not found, or when an Excel sheet is not found

Notes

• EPPlus requires setting the license context in your app before using: OfficeOpenXml.ExcelPackage.LicenseContext = LicenseContext.NonCommercial; This library internally sets a non-commercial personal license for convenience, but you should configure it according to your usage scenario.