title: Correct use of multimapping in Dapper
body: <p>I'm trying to use the multimapping feature of Dapper to return a list of ProductItems and associated Customers.</p>
  <pre class="lang-cs prettyprint-override"><code>[Table(&quot;Product&quot;)]
  public class ProductItem
  {
      public decimal ProductID { get; set; }        
      public string ProductName { get; set; }
      public string AccountOpened { get; set; }
      public Customer Customer { get; set; }
  } 
  
  public class Customer
  {
      public decimal CustomerId { get; set; }
      public string CustomerName { get; set; }
  }
  </code></pre>
  <p>My Dapper code:</p>
  <pre class="lang-cs prettyprint-override"><code>var sql = @&quot;select * from Product p 
              inner join Customer c on p.CustomerId = c.CustomerId 
              order by p.ProductName&quot;;
  
  var data = con.Query&lt;ProductItem, Customer, ProductItem&gt;(
      sql,
      (productItem, customer) =&gt; {
          productItem.Customer = customer;
          return productItem;
      },
      splitOn: &quot;CustomerId,CustomerName&quot;
  );
  </code></pre>
  <p>This works fine, but I seem to have to add the complete column list to the &quot;splitOn&quot; parameter to return all the customers' properties.  If I don't add &quot;CustomerName&quot;, it returns null.  Am I misunderstanding the core functionality of the multimapping feature? I don't want to have to add a complete list of column names each time.</p>