Some days ago I had a problem while mapping domain objects to DTO by automapper. My environment was an Asp.Net Core 3 Web Api project. I created an own profiles class where I stored my mapping logic. In the startup class I registered the mapper service. When running project my source of type List<Product> should be mapped to List<ProductDTO>. But the API always returned an empty list even if the source was filled correctly.
Profile:
CreateMap<Product, ProductDTO>(); CreateMap<List<Product>, List<ProductDTO>>();
The mistake was the second line in my profile class. Automapper automatically maps collections you don’t have to create a map for this case.