zeroadam

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AutoMapper - mapping nullable properties in c/dotnet@programming.dev
[–] zeroadam@programming.dev 1 points 1 year ago* (last edited 1 year ago) (1 children)

So.. When I change...

.ForMember(ee => ee.ExampleId, options => options.MapFrom(ed => ed.ExampleProperty != null ? ed.ExampleProperty.ExampleId : (long?)null))

TO:

.ForMember(ee => ee.ExampleId, options => options.MapFrom(ed => ed.ExampleProperty?.ExampleId))

I am presented with: CS8072 - An expression tree lambda may not contain a null propagating operator.

AutoMapper - mapping nullable properties in c/dotnet@programming.dev
[–] zeroadam@programming.dev 1 points 1 year ago (4 children)

I can certainly test this. My question would then be, will this result in actually mapping a null in the dto, or would the .ExampleProperty? just "be null" and cause the long property to instantiate to 0?

14
AutoMapper - mapping nullable properties (programming.dev)
 

While implementing AutoMapper in some existing code, I came across the need to map to a nullable property. Other business logic relied on this particular long being null instead of 0. The DTO has a property that contains a (long)Id, but the Entity contains the virtual property as well as a nullable long? of the Id. Anyway after fumbling through a few tries, I finally came upon the solution and wanted to share it here.

In the MapperProfile for the direction of DTO to Entity you have to do a null check, but the trick for me was having to explicitly cast to (long?)null.

CreateMap<ExampleDto, ExampleEntity>().ForMember(ee => ee.ExampleId, options => options.MapFrom(ed => ed.ExampleProperty != null ? ed.ExampleProperty.ExampleId : (long?)null)).NoVirtualMap();

Hope someone else finds this helpful, and finds it here.

[Edited] Community Icon Poll - Part 3 in c/meta@programming.dev
[–] zeroadam@programming.dev 1 points 1 year ago

I like option 1 and option 2. Option 2 seems easier to differentiate, as others have mentioned.

YouTube channels worth following in c/csharp@programming.dev
[–] zeroadam@programming.dev 5 points 1 year ago

I enjoy Nick Chapsas videos as @canpolat@programming.dev mentions. Other videos that pop up end up being "day in the life" type stuff rather than instructional/information content.