NeoMapper 🪄

A small yet powerful generic mapper for .NET 8 written in C# with no external dependencies. Automatically maps entities ⇄ DTOs using extension methods, supporting attributes, type conversion, and collections.

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📦 Installation

NeoMapper is available on NuGet:

dotnet add package NeoMapper

NuGet Badge:

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🚀 Features

• Simple extension methods:
  • MapTo<TDest>() → creates a destination object from the source.
  • MapFrom(source) → fills an existing instance.
• Customizable attributes:
  • [MapIgnore] → ignores properties.
  • [MapName("OtherProperty")] → alias for different property names.
• Built-in type conversion:
  • Nullables (int?, DateTime?, etc.).
  • Enums ↔ string/numbers.
  • Guid, DateTime, decimal, TimeSpan, etc.
• Collections: converts IEnumerable<T> to List<TDestination>.
• Recursive mapping: complex objects are mapped property by property.
• Custom converters: register your own conversion functions between types.

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🧑‍💻 Quick usage

using GenericMapper;

var user = new User
{
    Id = 7,
    FullName = "Ada Lovelace",
    CreatedAt = DateTime.UtcNow,
    Address = new Address { Street = "St. James's", City = "London" },
    Roles = new List<Role> { Role.Admin, Role.User }
};

// Entity → DTO
var dto = user.MapTo<UserDto>();

// DTO → Entity
var user2 = dto.MapTo<User>();

// Map onto existing instance
user2.MapFrom(new UserDto { Id = 7, Name = "Ada Byron" });

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🛠️ Attribute example

public sealed class UserDto
{
    public int Id { get; set; }
    [MapName("FullName")] // Map FullName from entity to Name in DTO
    public string Name { get; set; } = string.Empty;
    public string CreatedAt { get; set; } = string.Empty;
    public AddressDto? Address { get; set; }
    public List<string> Roles { get; set; } = new();
}

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🔧 Custom converters

MappingExtensions.RegisterConverter<Role, string>(r => r.ToString());
MappingExtensions.RegisterConverter<string, Role>(s => Enum.Parse<Role>(s, true));

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📂 Recommended structure

• src/NeoMapper/ObjectMapper.cs → main NeoMapper code.
• DTOs and Entities in their respective layers.

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📜 License

MIT – You can use and adapt it freely.

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✨ Contributions

Ideas and improvements are welcome! You can add:

• Support for fluent configuration expressions.
• Advanced date/time format handling.
• Direct serialization from JSON.

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NeoMapper: Transform your objects as if by magic. 🪄