AutoMapper Map If Not Null, Otherwise Custom Convert

c# automapper
RPM1984 picture RPM1984 · Jul 19, 2012 · Viewed 30.4k times · Source

Here's my code:

Mapper.CreateMap<Foo, Foo2>()
   .ForMember(dest => dest.Bar, opt => opt.MapFrom(src => src.Bar == null ? new BarViewModel() : src.Bar))

Basically, "BarViewModel" has a parameterless ctor which sets up properties in the class.

So i'm trying to say to AutoMapper:

If the value is null, then use the ctor for the class. otherwise use the mapping you have in place

The above is giving me a C# compiler error. And i'm guessing a cast wouldn't work either.

So is there a AutoMapper trick to do this?

Worst case i could remove that mapping for that property, and just do:

var mapped = Mapper.Map<Foo,Foo2>(src);
if (mapped.Bar == null) mapped.Bar = new BarViewModel();

But that's a tad ugly.

Ideas?

Answer

k0stya picture k0stya · Jul 19, 2012

You can use custom value resolver. The following should work:

Mapper.CreateMap<Foo, Foo2>()
   .ForMember(dest => dest.Bar, opt => opt.ResolveUsing(src => src.Bar == null ? new Bar() : Mapper.Map<Bar,Bar2>(src.Bar)))

Related questions

Ignore mapping one property with Automapper

I'm using Automapper and I have the following scenario: Class OrderModel has a property called 'ProductName' that isn't in the database. So when I try to do the mapping with: Mapper.CreateMap<OrderModel, Orders>(); It generates an exception : "…

Read More
How to set up Automapper in ASP.NET Core

I'm relatively new at .NET, and I decided to tackle .NET Core instead of learning the "old ways". I found a detailed article about setting up AutoMapper for .NET Core here, but is there a more simple walkthrough for a …

Read More
Simple Automapper Example

I am having a hard time to understand how to map certain objects. Please answer some questions about this simple example. Example code class User { private int id; private string name; } class Group { private int id; private string name; private …

Read More