title: Check if an item exist in observable collection
body: <p>I've an observable collection that is populated dynamically. I populate it through a list of items called <code>events</code>. There are situations where an event could be deleted from the events list, and when this happens I need to also remove it from the observable collection.</p>
  
  <p>What I'm looking for is a simple and speedy way to do this. I tried the following:</p>
  
  <pre><code> bool exist = events.Where(x =&gt; x.Home == obCollection[x].Home).Any();
  </code></pre>
  
  <p>but I cannot access <code>obCollection</code> through the <code>x</code> element because I need an index, and <code>x</code> is the actual item. I need to fix this to produce the correct elements, and afterwards I need to remove the remaining elements in the observable collection.</p>