title: MongoDB C# - Getting BsonDocument for an Element that doesn't exist
body: <p>So I have a BsonDocument b (let's say it has FirstName, LastName, Age), which you could access as b["FirstName"], etc...</p>
  
  <p>If I try to do b["asdfasdf"] (which doesn't exist of course), instead of returning null, it errors out the app.  What's the correct way to check?  Do I really have to do a try/catch?</p>