Question

Let’s say I have a Domain Object like this:

public class Product
{
   public int Id {get;set;}
   public string Name {get;set;}
   public string Description {get;set;}
   public int DisplayOrder {get;set;}
   //Lots of other properties
}

For my view however, I want to use 2 different view models that use different properties of the product class.

public class ProductViewModel1
{
   public int Id {get;set;}
   public string Name {get;set;}
   //A mix of some of the other properties
}
public class ProductViewModel2
{
   public int Id {get;set;}
   public string Description {get;set;}
   //A different mix of the other properties
}

For Automapper:

Mapper.CreateMap<Product, ProductViewModel1>();
Mapper.CreateMap<Product, ProductViewModel2>();

Question(s):
Is it necessary to add all the ignored properties to CreateMap? Is there significant overhead if this is not done on larger objects? Thanks.

Answer 1

Its not necessary, but when you unit test your mappings (or assert at runtime to make sure they are accurate) the Ignores are required for it to succeed.

Mapper.AssertConfigurationIsValid();

You can read more about verifying AutoMapper configuration is correct here:

http://automapper.codeplex.com/wikipage?title=Configuration%20Validation