ExcelMapper 5.2.581

dotnet add package ExcelMapper --version 5.2.581
NuGet\Install-Package ExcelMapper -Version 5.2.581
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="ExcelMapper" Version="5.2.581" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add ExcelMapper --version 5.2.581
#r "nuget: ExcelMapper, 5.2.581"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install ExcelMapper as a Cake Addin
#addin nuget:?package=ExcelMapper&version=5.2.581

// Install ExcelMapper as a Cake Tool
#tool nuget:?package=ExcelMapper&version=5.2.581


NuGet version Build status codecov.io netstandard2.0 net462

A library to map POCO objects to Excel files.


  • Read and write Excel files
  • Uses the pure managed NPOI library instead of the Jet database engine (NPOI users group)
  • Map to Excel files using header rows (column names) or column indexes (no header row)
  • Map nested objects (parent/child objects)
  • Optionally skip blank lines when reading
  • Preserve formatting when saving back files
  • Optionally let the mapper track objects
  • Map columns to properties through convention, attributes or method calls
  • Use custom or builtin data formats for numeric and DateTime columns
  • Map formulas or formula results depending on property type
  • Map JSON
  • Fetch/Save dynamic objects
  • Use records
  • Provide custom object factories

Read objects from an Excel file

var products = new ExcelMapper("products.xlsx").Fetch<Product>();

This expects the Excel file to contain a header row with the column names. Objects are read from the first worksheet. If the column names equal the property names (ignoring case) no other configuration is necessary. The format of the Excel file (xlsx or xls) is autodetected.

Map to specific column names

public class Product
  public string Name { get; set; }
  public int NumberInStock { get; set; }
  public decimal Price { get; set; }

This maps the column named Number to the NumberInStock property.

Map to column indexes

Column indexes start at 1.

public class Product
    public string Name { get; set; }
    public int NumberInStock { get; set; }
    public decimal Price { get; set; }

var products = new ExcelMapper("products.xlsx") { HeaderRow = false }.Fetch<Product>();

Note that column indexes don't need to be consecutive. When mapping to column indexes, every property needs to be explicitly mapped through the ColumnAttribute attribute or the AddMapping() method. You can combine column indexes with column names to specify an explicit column order while still using a header row.

Map through method calls

var excel = new ExcelMapper("products.xls");
excel.AddMapping<Product>("Number", p => p.NumberInStock);
excel.AddMapping<Product>(1, p => p.NumberInStock);
excel.AddMapping(typeof(Product), "Number", "NumberInStock");
excel.AddMapping(typeof(Product), ExcelMapper.LetterToIndex("A"), "NumberInStock");

Multiple mappings

You can map a single column to multiple properties but you need to be aware of what should happen when mapping back from objects to Excel. To specify the single property you want to map back to Excel, add MappingDirections.ExcelToObject in the Column attribute of all other properties that map to the same column. Alternatively, you can use the FromExcelOnly() method when mapping through method calls.

public class Product
    public decimal Price { get; set; }
    [Column("Price", MappingDirections.ExcelToObject)]
    public string PriceString { get; set; }

// or

excel.AddMapping<Product>("Price", p => p.PriceString).FromExcelOnly();

Column attributes are inherited by default, resulting in multiple mappings for a single overridden property if you add a Column attribute to the property in base and derived classes. To prevent this, set the Inherit property to false on the Column attribute in the base class.

Dynamic mapping

You don't have to specify a mapping to static types, you can also fetch a collection of dynamic objects.

var products = new ExcelMapper("products.xlsx").Fetch(); // -> IEnumerable<dynamic>
products.First().Price += 1.0;

The returned dynamic objects are instances of ExpandoObject with an extra property called __indexes__ that is a dictionary specifying the mapping from property names to column indexes. If you set the HeaderRow property to false on the ExcelMapper object, the property names of the returned dynamic objects will match the Excel "letter" column names, i.e. "A" for column 1 etc.

Save objects

var products = new List<Product>
    new Product { Name = "Nudossi", NumberInStock = 60, Price = 1.99m },
    new Product { Name = "Halloren", NumberInStock = 33, Price = 2.99m },
    new Product { Name = "Filinchen", NumberInStock = 100, Price = 0.99m },

new ExcelMapper().Save("products.xlsx", products, "Products");

This saves to the worksheet named "Products". If you save objects after having previously read from an Excel file using the same instance of ExcelMapper the style of the workbook is preserved allowing use cases where an Excel template is filled with computed data.

Track objects

var products = new ExcelMapper("products.xlsx").Fetch<Product>().ToList();
products[1].Price += 1.0m;

Ignore properties

public class Product
    public string Name { get; set; }
    public int Number { get; set; }
    public decimal Price { get; set; }

// or

var excel = new ExcelMapper("products.xlsx");
excel.Ignore<Product>(p => p.Price);

Use specific data formats

public class Product
    public DateTime Date { get; set; }

    public decimal Number { get; set; }

You can use both builtin formats and custom formats. The default format for DateTime cells is 0x16 ("m/d/yy h:mm").

Map formulas or results

Formula columns are mapped according to the type of the property they are mapped to: for string properties, the formula itself (e.g. "A1+B1") is mapped, for other property types the formula result is mapped. If you need the formula result in a string property, use the FormulaResult attribute.

public class Product
    public string Result { get; set; }

// or

excel.AddMapping<Product>("Result" p => p.Result).AsFormulaResult();

If you want to save formulas you need to use the FormulaAttribute attribute or call AsFormula() if mapping manually. It's not needed if you only want to map from Excel to objects (deserialize).

public class Product
    public string Formula { get; set; }

// or

excel.AddMapping<Product>("Formula" p => p.Formula).AsFormula();

☝️ The string values of formula properties must not start with the = sign. So instead of =A1+B1 set the property's value to A1+B1.

Custom mapping

If you have specific requirements for mapping between cells and objects, you can use custom conversion methods. Here, cells that contain the string "NULL" are mapped to null:

public class Product
    public DateTime? Date { get; set; }

excel.AddMapping<Product>("Date", p => p.Date)
    .SetCellUsing((c, o) =>
        if (o == null) c.SetCellValue("NULL"); else c.SetCellValue((DateTime)o);
    .SetPropertyUsing(v =>
        if ((v as string) == "NULL") return null;
        return Convert.ChangeType(v, typeof(DateTime), CultureInfo.InvariantCulture);

Header row and data row range

You can specify the row number of the header row using the property HeaderRowNumber (default is 0). The range of rows that are considered rows that may contain data can be specified using the properties MinRowNumber (default is 0) and MaxRowNumber (default is int.MaxValue). The header row doesn't have to fall within this range, e.g. you can have the header row in row 5 and the data in rows 10-20.


You can easily serialize to and from JSON formatted cells by specifying the Json attribute or AsJson() method.

public class ProductJson
    public Product Product { get; set; }

// or

var excel = new ExcelMapper("products.xls");
excel.AddMapping<ProductJson>("Product", p => p.Product).AsJson();

This also works with lists.

public class ProductJson
    public List<Product> Products { get; set; }

Name normalization

If the header cell values are not uniform, perhaps because they contain varying amounts of whitespace, you can specify a normalization function that will be applied to header cell values before mapping to property names. This can be done globally or for specific classes only.

excel.NormalizeUsing(n => Regex.Replace(n, "\w", ""));

This removes all whitespace so that columns with the string " First Name " map to a property named FirstName.


Records are supported. If the type has no default constructor (as is the case for positional records) the constructor with the highest number of arguments is used to initialize objects. This constructor must have a parameter for each of the mapped properties with the same name as the corresponding property (ignoring case). The remanining parameters will receive the default value of their type.

Nested objects

Nested objects are supported and should work out of the box for most use cases. For example, if you have a sheet with columns Name, Street, City, Zip, Birthday, you can map to the following class hierarchy without any configuration:

public class Person
    public string Name { get; set; }
    public DateTime Birthday { get; set; }
    public Address Address { get; set; }

public class Address
    public string Street { get; set; }
    public string City { get; set; }
    public string Zip { get; set; }

var customers = new ExcelMapper("customers.xlsx").Fetch<Person>();

This works with records, too:

public record Person(string Name, DateTime Birthday, Address Address);
public record Address(string Street, string City, string Zip);

Object factories

You can specify a custom object factory for any type which will be used to create object instances for mapped properties of that type. This can be useful to handle cases where object creation is otherwise not possible (such as for properties that have interface types) or where you want to execute specific initialization logic.

public class Person
    public string Name { get; set; }
    public IAddress Address { get; set; }

excel.CreateInstance<IAddress>(() => new Address());
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.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
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NuGet packages (7)

Showing the top 5 NuGet packages that depend on ExcelMapper:

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Halifax Service Foundation Excel/CSV library

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Open-Source eCommerce Platform on .NET Core, MongoDB, AWS DocumentDB, Azure CosmosDB, LiteDB & Vue.js
Version Downloads Last updated
5.2.581 9,490 4/12/2024
5.2.580 9,611 3/25/2024
5.2.568 17,323 2/12/2024
5.2.564 26,151 12/13/2023
5.2.542 61,124 9/12/2023
5.2.535 12,195 8/24/2023
5.2.528 12,798 7/31/2023
5.2.483 189,154 2/8/2023
5.2.482 28,755 1/18/2023
5.2.472 38,012 12/13/2022
5.2.471 7,244 12/5/2022
5.2.467 26,639 11/17/2022
5.2.429 63,475 8/24/2022
5.2.427 6,079 8/16/2022
5.2.415 51,830 6/30/2022
5.2.413 1,292 6/29/2022
5.2.411 40,918 6/22/2022
5.2.405 75,610 5/24/2022
5.2.404 4,676 5/19/2022
5.2.403 4,793 5/12/2022
5.2.394 8,356 5/4/2022
5.2.393 7,341 4/27/2022
5.2.390 12,370 4/20/2022
5.2.388 103,017 4/19/2022
5.2.387 3,109 4/19/2022
5.2.383 46,581 3/21/2022
5.2.375 59,224 2/22/2022
5.2.352 112,780 11/30/2021
5.2.337 50,920 11/8/2021
5.2.328 60,925 9/23/2021
5.2.314 80,631 6/14/2021
5.2.313 5,551 6/12/2021
5.2.298 55,195 4/22/2021
5.1.294 5,880 4/19/2021
5.1.289 7,882 4/14/2021
5.1.279 19,699 3/23/2021
5.1.278 25,375 2/26/2021
5.1.277 1,118 2/25/2021
5.1.270 11,428 2/10/2021
5.1.267 1,035 2/9/2021
5.1.265 1,027 2/9/2021
5.1.264 1,113 2/9/2021
5.1.263 2,719 2/8/2021
5.1.253 26,859 1/15/2021
5.1.241 5,759 12/22/2020
5.1.227 12,011 11/25/2020
5.1.218 15,962 11/3/2020
5.1.216 1,197 11/2/2020
5.1.210 2,218 10/20/2020
5.1.194 9,233 10/15/2020
5.1.180 3,890 9/24/2020
5.1.174 4,617 8/19/2020
5.1.173 1,825 8/16/2020
5.0.166 29,892 7/1/2020
5.0.160 49,586 5/13/2020
5.0.151 61,528 4/6/2020
5.0.143 19,075 3/5/2020
5.0.141 3,953 3/1/2020
5.0.139 1,258 2/29/2020
5.0.138 1,243 2/29/2020
5.0.137 11,698 2/27/2020
5.0.118 73,333 12/7/2019
5.0.105 47,166 10/11/2019
5.0.92 41,592 9/17/2019
5.0.60 31,683 6/26/2019
5.0.46 17,193 4/2/2019
5.0.41 4,848 3/7/2019
4.0.39 2,947 2/6/2019
4.0.37 2,039 1/3/2019
4.0.34 3,981 11/26/2018
4.0.32 1,754 11/11/2018
4.0.31 1,648 11/5/2018
4.0.20 2,969 9/20/2018
1.0.18 1,735 9/12/2018
1.0.15 8,219 12/14/2015
1.0.7 3,796 11/29/2015