title: Linq to MongoDB Filter
body: <p>I have a MongoDB collection, listed below:</p>
  
  <pre><code>{ 
      "_id" : ObjectId("001"), 
      "ticker" : "MSFT=US", 
      "exchange" : "OTC", 
      "localtick" : "MSFT", 
      "compname" : "Microsoft", 
      "currency" : "USD", 
      "insertedtime" : ISODate("2016-06-13T23:10:09.341+0000")
  }
  { 
      "_id" : ObjectId("002"), 
      "ticker" : "TSLA=CA", 
      "exchange" : "TSX", 
      "localtick" : "TSLA", , 
      "compname" : "Tesla", 
      "currency" : "CAD", 
      "insertedtime" : ISODate("2016-06-13T23:10:09.809+0000")
  }
  </code></pre>
  
  <p>But when I try to do a filter in my query:</p>
  
  <pre><code>var documents = collection.AsQueryable()
              .Where(c =&gt; c["ticker"].ToString().Contains("=CA"));
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Unsupported filter: {document}{ticker}.ToString().Contains("=CA").
  </code></pre>
  
  <p>What should I be doing to get MongoDB to handshake with LINQ?</p>