title: What are the ramifications for not ignoring unused properties in Automapper?
body: <p>Let's say I have a Domain Object like this:</p>
  
  <pre><code>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
  }
  </code></pre>
  
  <p>For my view however, I want to use 2 different view models that use different properties of the product class.</p>
  
  <pre><code>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
  }
  </code></pre>
  
  <p>For Automapper:</p>
  
  <pre><code>Mapper.CreateMap&lt;Product, ProductViewModel1&gt;();
  Mapper.CreateMap&lt;Product, ProductViewModel2&gt;();
  </code></pre>
  
  <p><strong>Question(s):</strong>
  Is it necessary to add all the ignored properties to CreateMap?  Is there significant overhead if this is not done on larger objects?  Thanks.</p>