title: MongoDb: Cannot deserialize a 'ObjectId' from BsonType 'Int32'
body: <p>I create simple class:</p>
  
  <pre><code> public class User
  {       
    //  [BsonRepresentation(BsonType.ObjectId)]
      public ObjectId _id { get; set; }
  
      [BsonRepresentation(BsonType.String)]
      public String Name { get; set; }
  
      [BsonRepresentation(BsonType.String)]
      public string Email { get; set; }
  }
  </code></pre>
  
  <p>And then i try to get users collection:</p>
  
  <pre><code>  using (var cursor = await col.Find&lt;User&gt;(Builders&lt;User&gt;.Filter.Empty).ToCursorAsync())
              {
                  while (cursor.MoveNext())
                  {
                     //do work
                  }
              }
  </code></pre>
  
  <p>So, it thows exception:"Cannot deserialize a 'ObjectId' from BsonType 'Int32'" at line "ToCursorAsync()".</p>
  
  <p>What i am doing wrong?</p>