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Constructor mappings

Mapperly supports using parameterized constructors of mapping target types. Mapperly resolves the constructor to be used by the following priorities:

  • accessible constructors annotated with MapperConstructor
  • accessible parameterless constructors
  • accessible constructors ordered in descending by their parameter count
  • constructors with a System.ObsoleteAttribute attribute, unless they have a MapperConstructor attribute

The first constructor which allows the mapping of all parameters is used. Constructor parameters are mapped in a case insensitive matter.

Manual mapping configuration‚Äč

Manual mapping of source properties to constructor parameters can be configured with the MapProperty attribute. See example below

public class Car
{
public string ModelName { get; set; }
}

public record CarDto(string Model);

[Mapper]
public partial class CarMapper
{
[MapProperty(nameof(Car.ModelName), nameof(CarDto.Model))]
public partial CarDto ToDto(Car car);
}

If the target type is a normal class, where the constructor parameter name not necessarily matches the property name, you can identify the correct parameter name using a string literal.

public class Car
{
public string ModelName { get; set; }
}

public class CarDto
{
public CarDto(string model)
{
ModelName = model;
}

public string ModelName { get; }
}

[Mapper]
public partial class CarMapper
{
[MapProperty(nameof(Car.ModelName), "model")]
public partial CarDto ToDto(Car car);
}