AutoMapper

AutoMapper is an open-source library for the .NET platform that simplifies the transformation of data between objects (object-to-object mapping). It was developed by Jimmy Bogard in 2009. It automates conversions between data transfer objects (DTOs) and domain models used across different layers in software development, minimizing the need for manual code writing.

Why Do We Need AutoMapper?

In enterprise applications, database models (entities) and API models exposed to the external world (DTOs) are often not identical. Manually converting between them generates large amounts of repetitive code (boilerplate code). AutoMapper reduces code repetition simplifies maintenance lowers the risk of errors and improves code readability by performing these conversions through a single configuration.

How It Works

AutoMapper allows you to define mappings between source and destination classes. Once a mapping is defined the library automatically transforms fields between objects based on name and type compatibility.

In the above code example AutoMapper automatically maps the Name and Email properties defined in the User class to the corresponding properties in the UserDto class.

Key Features

The key features of AutoMapper can be summarized as follows:

• Objects with matching field names and types are automatically mapped
• Manual configuration is possible when field names differ
• Nested object structures are automatically converted
• Collections such as lists and arrays are automatically transformed
• Two-way mapping can be defined in a single line of code
• Direct conversion to DTOs is possible via LINQ queries

Current Usage

AutoMapper is one of the most widely used libraries in modern ASP.NET Core projects. It is particularly favored in layered architectures. It can be easily accessed through the NuGet Package Manager in Visual Studio and is continuously updated by the open-source community.