mongodb c＃驱动程序SelectMany linq运算符

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();

Answer 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();

Answer 2

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();