title: Automapper: mapping collection and passing parameter
body: <p>I am trying to map one entity to another (which has one additional field).</p>
  
  <pre><code>Group {
      int Id;
  }
  
  GroupExtended {
     int Id;
     string Description;
  }
  </code></pre>
  
  <p>So I do the mapping in loop:  </p>
  
  <pre><code>foreach (var group in groups)
  {
       var result = mapper.Map&lt;Group, GroupExtended&gt;(group,
                          opt =&gt; opt.AfterMap((src, dest) =&gt; dest.Description = someValue));
  }
  </code></pre>
  
  <p>Is that possible to map entire IEnumerable, and still passing an the value ?
  I tried this:</p>
  
  <pre><code>var result = mapper.Map&lt;List&lt;GroupExtended&gt;&gt;(groups,
                          opt =&gt; opt.AfterMap((src, dest) =&gt; dest.Description = someValue));
  </code></pre>
  
  <p>But it has an error on <code>dest.Description</code> : 'object' does not contain definition of "Description"</p>