Table of Contents
How does AutoMapper work?
AutoMapper in C# is a library used to map data from one object to another. It acts as a mapper between two objects and transforms one object type into another. It converts the input object of one type to the output object of another type until the latter type follows or maintains the conventions of AutoMapper.
How does AutoMapper handle null?
Null substitution allows you to supply an alternate value for a destination member if the source value is null anywhere along the member chain. This means that instead of mapping from null, it will map from the value you supply.
Does AutoMapper create new instance?
When these collections map from the ViewModel to the Model, rather than map properties, a new instance of a UserPreference object is created from the ViewModel, rather than update the existing object with the ViewModel properties. And automapper configuration: Mapper.
What is ReverseMap AutoMapper?
By calling ReverseMap , AutoMapper creates a reverse mapping configuration that includes unflattening: var customer = new Customer { Name = “Bob” }; var order = new Order { Customer = customer, Total = 15.8m }; var orderDto = mapper.
What is opt null substitute in automapper?
It “allows you to supply an alternate value for a destination member if the source value is null anywhere along the member chain” (taken from the AutoMapper manual ). cfg.CreateMap () .ForMember (dest => dest.Value, opt => opt.NullSubstitute (new IdNameDest { Id = src.Id }));
Does automapper support custom value resolvers for Destination members?
However, if this logic pertains only to the mapping operation, it would clutter our source types with unnecessary behavior. In these cases, AutoMapper allows for configuring custom value resolvers for destination members.
What does it mean to map from NULL instead of null?
This means that instead of mapping from null, it will map from the value you supply. The substitute is assumed to be of the source member type, and will go through any mapping/conversion after to the destination type.
What is the resolutioncontext in automapper?
The ResolutionContext contains all of the contextual information for the current resolution operation, such as source type, destination type, source value and so on. An example implementation: Once we have our IValueResolver implementation, we’ll need to tell AutoMapper to use this custom value resolver when resolving a specific destination member.