title: how to know if my linq query returns null
body: <p>I have this linq query :</p>
  
  <pre><code>var myQuery = from Q in myDataContext
            select Q.Name
  </code></pre>
  
  <p>and when I try to do this :
      listView.ItemsSource = myQuery</p>
  
  <p>it sometimes throws an exception because there are no elements in <code>myQuery</code></p>
  
  <p>I tried many ways like : <code>if(myQuery.count!=0)</code>  or <code>if(myQuery.Any())</code> 
  but nothing worked , so how can I determine if my Query return null ?</p>