mongodb c# driver SelectMany linq operator

Question

Hi I upgrade my mongodb driver to 2.2.3.3 version and I want to use SelectMany operator to query nested document.But when I try to execute my query I get "The SelectMany query operator is not supported error". Here is my code:

MongoDatabase database;
var client = new MongoClient("mongodb://myconnection");
var server = client.GetServer();
database = server.GetDatabase("MyDB");
MongoCollection<DGTable> collection;
collection = database
    .GetCollection<DGTable>(typeof(DGTable).Name);

var result = collection.AsQueryable()
    .SelectMany(p => p.TableColumns);
var abc = result.ToList();

If the error says "not supported," doesn't that tell you what the problem is? What is your question? — Kenneth K.
– Kenneth K., Commented Apr 15, 2016 at 12:50
As I know latest version 2.2.3.3 mongodb c# driver support SelectMany ability,and I want to understand ,Do I wrong useage of SelectMany or may be I have to do different things to use SelectMany. — Bilgehan
– Bilgehan, Commented Apr 15, 2016 at 14:23

Maarten · Accepted Answer · 2016-04-15 13:20:15Z

1

You can postpone the call to .SelectMany(...) until after you have the data. The method call doesn't increase the amount of data or does some db-specific-performance operation, so there is no explicit reason to call it within the query.

var result = collection.AsQueryable()
    .Select(p => p.TableColumns)
    .ToList();
var abc = result
    .SelectMany(p => p)
    .ToList();

edited Apr 15, 2016 at 13:20

answered Apr 15, 2016 at 12:59

Maarten

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Bilgehan · Accepted Answer · 2016-04-18 12:20:14Z

0

I find solution,I have some obsolute methods and I upgrade my code to new methods then it works

      var client = new MongoClient("mongodb://myconnection");

        var db = client.GetDatabase("mydb");
        var col = db.GetCollection<DGTable>("DGTable");

        var sadsdadas = col.AsQueryable().SelectMany(p => p.TableColumns).ToList();

answered Apr 18, 2016 at 12:20

Bilgehan

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