Automapper configuration for interesting nested object scenario - automapper

Question

I have an interesting scenario and the answer isn't jumping out at me. I've looked for other similar questions but none seem to address this type of issue.
Before you ask, I do not have control over the source class layout.
My source object looks like this:
class Class1
{
string string1
string string2
string string3
string string4
string string5
string string6
}
class Class2
{
string foo
string bar
}
class Class3 //The source object!!
{
Class1 Inner1
Class2 Inner2
}
And my destination looks like this:
class Destination
{
string string1
string string2
string string3
string string4
string string5
string string6
string string7
}
In reality, Inner1 is a huge class and almost a perfect match - except for a couple exceptions. I'd like to use Automapper to directly copy everything from Inner1 to Destination using default matching, but also copy Inner2.foo to Destination.string6 and Inner2.bar to Destination.string7.
EDIT: I should add that right now I am mapping Inner1 to Destination and then doing a couple manual property copies outside of Automapper.
Any suggestions are appreciated.

Answer 1

Guessing you currently have something like this:
Mapper.CreateMap<Inner1, Destination>();
...
var inner1 = GetInner1();
var destination = Mapper.Map<Destination>(inner1);
// now do manual hydration on destination using inner2 instance...
You might be able to get away with this:
Mapper.CreateMap<Inner1, Destination>();
Mapper.CreateMap<Inner2, Destination>()
.ForMember(d => d.string6, o => o.ResolveUsing(s => s.foo))
.ForMember(d => d.string7, o => o.ResolveUsing(s => s.bar))
;
...
var inner1 = GetInner1();
var destination = Mapper.Map<Destination>(inner1);
var inner2 = GetInner2();
Mapper.Map(inner2, destination);