title: the best overloaded method match for List<T>.Add(T) has some Invalid arguments
body: <p>I defined a <code>List</code> like this:</p>
  
  <pre><code>List&lt;Agahii.Ads&gt; ads = new List&lt;Agahii.Ads&gt;();
  </code></pre>
  
  <p>Then I want to fill it with the result of a LINQ query:</p>
  
  <pre><code>for (int i = 0; i &lt; adid.Count(); i ++ )
  {
        var dd = adid[i];
        var cc = (from a in context.Ads where a.AdID == dd select a).ToList();
  
        ads.Add(cc);     // error appears here
  };
  </code></pre>
  
  <p>error appears in the <code>ads.Add(cc);</code> line.</p>
  
  <blockquote>
    <p>error: the best overloaded method match for System.Collections.Generic.List.Add(Agahii.Ads) has some Invalid arguments</p>
  </blockquote>