MongoDB/C# get all values of a certain key in all documents

I have a MongoDB collection called "employees" where there are documents like this:

{ 
  "_id": "4dc077b07701540f34000001", 
  "FullName": "Fullname...", 
  "FirstName": "First name...", 
  "LastName": "Last name...", 
  "Title": "Title... ",
  "Location": "Location...", 
  "Customer": "Customer...", 
  "Phone": "Phone...", 
  "CellPhone" : "Cellphone...", 
  "EMail": "E-mail..." 
}

I am trying to make a method that does a foreach loop on all documents in the collection and puts each value of the FullName-key and adds it to a List.

        List<string> listed = new List<string>();
        IMongoCollection collection = _db.GetCollection("employees");
        //var开发者_如何学运维 list = collection.FindAll().Documents.ToList();
        var persons = from p in collection.AsQueryable()
                      select p["FullName"];
        //foreach (var lt in list)
        foreach (var name in persons)
        {
            //listed.Add(lt["FullName"].ToString());
            listed.Add(name.ToString());
        }
        return listed;

Above is the code I have tried, the commented-code returns a NullReferenceException, the uncommented code returns the whole document in a list.

My question is: What kind of query must I do to get each value for every key called "FullName" into a list? I am using the current MongoDB stable version on Windows 7, and I am using the MongoDB-CSharp community driver. All help and pointers are appreciated!

---

var collection = _db.GetCollection("employees");
return (from p in collection.AsQueryable()
         select p["FullName"]).toList();

Should do it?

However you should consider using the generic methods as seen in:

http://www.mongodb.org/display/DOCS/CSharp+Driver+Tutorial#CSharpDriverTutorial-GetCollectionmethod