EPPlus.Core.Extensions

Installation 
It's as easy as PM> Install-Package EPPlus.Core.Extensions from nuget
Dependencies
.NET Framework 4.6.1 EPPlus >= 4.5.2.1
.NET Standard 2.0 EPPlus.Core >= 1.5.4
Documentation and Examples
The project will be documented soon. For now, just look at the test project (EPPlus.Core.Extensions.Tests). It has just enough examples to show you how to use these extension methods.
Basic examples:
public class PersonDto
{
[ExcelTableColumn("First name")]
[Required(ErrorMessage = "First name cannot be empty.")]
[MaxLength(50, ErrorMessage = "First name cannot be more than {1} characters.")]
public string FirstName { get; set; }
[ExcelTableColumn("Last name")]
public string LastName { get; set; }
[ExcelTableColumn(3)]
[Range(1900, 2050, ErrorMessage = "Please enter a value bigger than {1}")]
public int YearBorn { get; set; }
public decimal NotMapped { get; set; }
} - Converting from Excel to list of objects
// Direct usage:
excelPackage.ToList<PersonDto>(configuration => configuration.SkipCastingErrors());
// Specific worksheet:
excelPackage.GetWorksheet("Persons").ToList<PersonDto>(); - From a list of objects to Excel package
List<PersonDto> persons = new List<PersonDto>();
// Convert list into ExcelPackage
ExcelPackage excelPackage = persons.ToExcelPackage();
// Convert list into byte array
byte[] excelPackageXlsx = persons.ToXlsx();
// Generate ExcelPackage with configuration
List<PersonDto> pre50 = persons.Where(x => x.YearBorn < 1950).ToList();
List<PersonDto> post50 = persons.Where(x => x.YearBorn >= 1950).ToList();
ExcelPackage excelPackage = pre50.ToWorksheet("< 1950")
.WithConfiguration(configuration => configuration.WithColumnConfiguration(x => x.AutoFit()))
.WithColumn(x => x.FirstName, "First Name")
.WithColumn(x => x.LastName, "Last Name")
.WithColumn(x => x.YearBorn, "Year of Birth")
.WithTitle("< 1950")
.NextWorksheet(post50, "> 1950")
.WithColumn(x => x.LastName, "Last Name")
.WithColumn(x => x.YearBorn, "Year of Birth")
.WithTitle("> 1950")
.ToExcelPackage(); - Generating an Excel template from ExcelWorksheetAttribute marked classes
[ExcelWorksheet("Stocks")]
public class StocksDto
{
[ExcelTableColumn("SKU")]
public string Barcode { get; set; }
[ExcelTableColumn]
public int Quantity { get; set; }
}
// To ExcelPackage
ExcelPackage excelPackage = Assembly.GetExecutingAssembly().GenerateExcelPackage(nameof(StocksDto));
// To ExcelWorksheet
using(var excelPackage = new ExcelPackage()){
ExcelWorksheet worksheet = excelPackage.GenerateWorksheet(Assembly.GetExecutingAssembly(), nameof(StocksDto));
}