Philiprehberger.Mapper

Ultra-simple object-to-object mapper with convention-based mapping and fluent overrides.

Installation

dotnet add package Philiprehberger.Mapper

Usage

using Philiprehberger.Mapper;

// Convention-based mapping — properties matched by name
var order = new Order { Id = 1, CustomerName = "Alice", Total = 99.99m };
var dto = Mapper.Map<Order, OrderDto>(order);
// dto.Id = 1, dto.CustomerName = "Alice", dto.Total = 99.99m

Map to Existing Object

var existing = new OrderDto { Notes = "Keep this" };
Mapper.Map(order, existing);
// existing.Id = 1, existing.Notes = "Keep this"

Fluent Configuration

Mapper.Configure<Order, OrderDto>(cfg => cfg
    .Map(src => src.Name, dest => dest.CustomerName)
    .Ignore(dest => dest.InternalCode)
    .MapFrom<string, string>(dest => dest.FullAddress, src => $"{src.Street}, {src.City}")
);

var dto = Mapper.Map<Order, OrderDto>(order);

Collection Mapping

var orders = new List<Order> { order1, order2, order3 };

// Map to List
List<OrderDto> dtos = Mapper.MapList<Order, OrderDto>(orders);

// Map to Array
OrderDto[] array = Mapper.MapArray<Order, OrderDto>(orders);

// Map to lazy IEnumerable
IEnumerable<OrderDto> enumerable = Mapper.MapEnumerable<Order, OrderDto>(orders);

Nested Object Mapping

Complex properties are recursively mapped when source and destination have matching property names with different complex types:

public class Order { public Address ShippingAddress { get; set; } }
public class OrderDto { public AddressDto ShippingAddress { get; set; } }

var dto = Mapper.Map<Order, OrderDto>(order);
// dto.ShippingAddress is mapped from order.ShippingAddress recursively

Custom Value Converters

public class StringToDateConverter : IValueConverter<string, DateTime>
{
    public DateTime Convert(string source) => DateTime.Parse(source);
}

Mapper.Configure<Order, OrderDto>(cfg => cfg
    .UseConverter<string, DateTime>(new StringToDateConverter()));

var dto = Mapper.Map<Order, OrderDto>(order);
// String properties are converted to DateTime using the registered converter

Flattening

Nested properties are automatically flattened by naming convention:

public class Order { public Address ShippingAddress { get; set; } }
public class Address { public string City { get; set; } }
public class FlatDto { public string ShippingAddressCity { get; set; } }

var dto = Mapper.Map<Order, FlatDto>(order);
// dto.ShippingAddressCity = order.ShippingAddress.City

Diagnostics

var unmapped = MapperDiagnostics.GetUnmappedProperties<Order, OrderDto>();
MapperDiagnostics.ValidateMapping<Order, OrderDto>();

API

Mapper

Method	Description
Map<TSource, TDest>(source)	Maps source to a new destination instance
Map<TSource, TDest>(source, dest)	Maps source onto an existing destination
MapList<TSource, TDest>(source)	Maps a collection to a List<TDest>
MapArray<TSource, TDest>(source)	Maps a collection to a TDest[] array
MapEnumerable<TSource, TDest>(source)	Maps a collection to a lazy IEnumerable<TDest>
Configure<TSource, TDest>(configure)	Registers fluent mapping overrides
Reset()	Clears all configurations and cached mappings

MappingConfiguration<TSource, TDestination>

Method	Description
Map<T>(source, dest)	Explicitly maps a source property to a destination property
Ignore(member)	Excludes a destination property from mapping
MapFrom<TSrc, TDest>(dest, resolver)	Maps a destination property using a custom resolver function
UseConverter<TSrc, TDest>(converter)	Registers a value converter for type pair conversion

IValueConverter<TSource, TDestination>

Method	Description
Convert(source)	Converts a source value to the destination type

MapperDiagnostics

Method	Description
GetUnmappedProperties<TSource, TDest>()	Returns unmapped destination property names
ValidateMapping<TSource, TDest>()	Throws if any destination properties are unmapped

MapToAttribute

Property	Description
DestinationType	The target type this class maps to

Development

dotnet build src/Philiprehberger.Mapper.csproj --configuration Release

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License

MIT