mongodb c# how to work with BSON document

bson, c#, mongodb

Solution

There are a few ways, but here's one:

 // build some test data
 BsonArray dataFields = new BsonArray { new BsonDocument { 
     { "ID" , ObjectId.GenerateNewId()}, { "NAME", "ID"}, {"TYPE", "Text"} } };
 BsonDocument nested = new BsonDocument {
     { "name", "John Doe" },
     { "fields", dataFields },
     { "address", new BsonDocument {
             { "street", "123 Main St." },
             { "city", "Madison" },
             { "state", "WI" },
             { "zip", 53711}
         }
     }
 };
 // grab the address from the document,
 // subdocs as a BsonDocument
 var address = nested["address"].AsBsonDocument;
 Console.WriteLine(address["city"].AsString); 
 // or, jump straight to the value ...
 Console.WriteLine(nested["address"]["city"].AsString);
 // loop through the fields array
 var allFields = nested["fields"].AsBsonArray ;
 foreach (var fields in allFields)
 {
     // grab a few of the fields:
     Console.WriteLine("Name: {0}, Type: {1}", 
         fields["NAME"].AsString, fields["TYPE"].AsString);
 }

You can often use the string indexer `["name-of-property"]` to walk through the fields and sub document fields. Then, using the `AsXYZ` properties to cast the field value to a particular type as shown above.

Problem

I've spent MANY hours looking for the answer... This is very easy in PHP but I just can't put it together in C#(I'm new to C# and mongo...) I'm trying to iterate through all levels of a stored document. The document looks like this: ``` { "_id": ObjectId("51f90101853bd88971ecdf27"), "fields": [ { "ID": ObjectId("51fd09498b080ee40c00514e"), "NAME": "ID", "TYPE": "Text" }, { "ID": ObjectId("51fd09a68b080ee40c0064db"), "NAME": "Title", "TYPE": "Text" }, { "ID": ObjectId("51fd09b28b080ee40c004d31"), "NAME": "Start Date", "TYPE": "Date" }, { "ID": ObjectId("51fd09c28b080ee40c007f2e"), "NAME": "Long Description", "TYPE": "Memo" } ], "name": "TODB", "updated": "Wed Jul 31 2013 08:20:17 GMT-0400 (Eastern Daylight Time)" } ``` I have no problem accessing the "name" and "updated" but can't figure out how to access the "fields" array. Code so far : ``` { MongoServer mongo = MongoServer.Create(); mongo.Connect(); var db = mongo.GetDatabase("forms"); mongo.RequestStart(db); var collection = db.GetCollection("forms"); var query = new QueryDocument("name", "TODB"); mongo.Disconnect(); } @foreach(BsonDocument item in collection.Find(query)) { @item.GetElement("name").Value @item.GetElement("_id").Value } ``` Again, I am able to access the name and _id just not any of the sub document values. Thanks in advance for any assistance! After I get the reading figured out, I am also going to want to write data....

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