MongoDB - Query within an in-memory BsonDocument

I am reading a single document into a BsonDocument object. Having read the document from MongoDB I'd like to query the document in-memory. My doc looks like this:

{
  "_id": {
    "$binary": "DYibd4bSz0SFXTTmY46gOQ==",
    "$type": "03"
  },
  "title": "XYZ 2011",
  "pages": [
    {
      "pagetype": "contactcapture",
      "pagetitle": "Contact",
      "questions": [
        {
          "qtype": "text",
          "text": "Firstname",
          "name": "firstname"
        },
        {
          "qtype": "text",
          "text": "Surname",
          "name": "surname"
        },
        {
          "qtype": "text",
          "text": "Company",
          "name": "companyname"
        }
      ]
   开发者_StackOverflow },
    {
      "pagetype": "question",
      "pagetitle": "Question 1",
      "questions": [
        {
          "qtype": "radio",
          "text": "What drink?",
          "name": "drink",
          "answers": [
            {
              "text": "Tea"
            },
            {
              "text": "Coffee"
            },
            {
              "text": "Hot chocolate"
            },
            {
              "text": "Water"
            }
          ]
        }
      ]
    },
    {
      "pagetype": "question",
      "pagetitle": "Question 2",
      "questions": [
        {
          "qtype": "check",
          "text": "Accompaniments?",
          "name": "accompaniments",
          "answers": [
            {
              "text": "Nuts"
            },
            {
              "text": "Crisps"
            },
            {
              "text": "Biscuits"
            }
          ]
        }
      ]
    },
    {
      "pagetype": "question",
      "pagetitle": "Question 3",
      "questions": [
        {
          "qtype": "radio",
          "text": "When would you like that?",
          "name": "when",
          "answers": [
            {
              "text": "Immediately"
            },
            {
              "text": "10 minutes"
            },
            {
              "text": "Half-an-hour"
            }
          ]
        },
        {
          "qtype": "text",
          "text": "Anything else with that?",
          "name": "anythingelse"
        }
      ]
    }
  ]
}

I want to get all pages that have a pagetype="question". I'm currently doing it as follows:

BsonDocument profileDocument= profilesCollection.FindOneByIdAs<MongoDB.Bson.BsonDocument>(binaryId);
BsonElement pagesElement = profileDocument.GetElement("pages");
BsonArray pages=profileDocument.GetElement("pages").Value.AsBsonArray;
foreach (BsonValue pageV in pages.Values)
{
    BsonDocument page = pageV.AsBsonDocument;
    if (page["pagetype"].AsString == "question")
    {
        sb.Append("<br />Question Page:" + page.ToJson());
    }
}

The code seems a little verbose and complex - I just wondered if there is a better way of doing this? Thanks

---

Assuming that the data type of profilesCollection is MongoCollection<BsonDocument>, you could shorten the code so something like this:

        var profileDocument = profilesCollection.FindOneById(binaryId);
        foreach (BsonDocument page in profileDocument["pages"].AsBsonArray) {
            if (page["pagetype"].AsString == "question") {
                sb.Append("<br />Question Page:" + page.ToJson());
            }
        }