Question

Let us say we have a simple business object:

class SimpleBO
{
   public string Field1{get;set;}
   public string Field2{get;set;}
}

Also we have a complex Aggregate like that:

class ComplexBO
{
    public SimpleBO SimpleBOField {get;set}
    public List<SomeClass> ObjectList {get;set;}
    public SomeClass Object {get;set;}
}

SomeClass itself has a reference of SimpleBO:

class SomeClass 
{
    public SimpleBO SimpleBOField {get;set}
}

Now in some part of my program I want to get a list of all distinct simple objects met inside a certain aggreggate. We are using automapper heavily but I did not manage to map it so far. May be a LINQ query is a better option? How would you solve this?

Answer 1

Assuming what you have is:

ComplexBO aggregate = ...

then you should just need:

var objects = aggregate.ObjectList.Select(x => x.SimpleBOField).Concat(
         new[] {aggregate.SimpleBOField, aggregate.Object.SimpleBOField }
    ).Distinct().ToList();

This will give you the distinct object references; if you need distinct value pairs, then either override Equals()/GetHashCode(), or cheat:

var objects = aggregate.ObjectList.Select(x => x.SimpleBOField).Concat(
         new[] {aggregate.SimpleBOField, aggregate.Object.SimpleBOField }
    ).Select(
         x => new {x.SimpleBOField.Field1, x.SimpleBOField.Field2}
    ).Distinct().Select(
         x => new SimpleBO {Field1 = x.Field1, Field2 = x.Field2}
    ).ToList();