Small example of using MongoDB dotnet driver (dotnet-core, MongoDB.Driver 2.4.1)

MongoDotnetDriver.cs

using System;
using System.Linq;
using MongoDB.Bson;
using MongoDB.Driver;

namespace ConsoleApplication
{

    public class Person {
        public ObjectId Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
        public override string ToString() {
            return "Person Name: " + Name + ", Age: " + Age;
        }
    }

    public class MongoDotnetDriver
    {
        public static void ListDatabases(MongoClient client) {
            Console.WriteLine("\n=== Databases ===");
            foreach(var db in client.ListDatabases().ToEnumerable()) {
                Console.WriteLine(" - " + db);
            }
        }

        public static void ListCollections(MongoClient client) {
            Console.WriteLine("\n=== Collections ===");
            var database = client.GetDatabase("test");
            foreach(var coll in database.ListCollections().ToEnumerable()) {
                Console.WriteLine(" - " + coll);
            }
        }

        public static void InsertDocuments(MongoClient client) {
            Console.WriteLine("\n=== Insert documents ===");
            var database = client.GetDatabase("test");
            var collection = database.GetCollection<BsonDocument>("dotnet");

            /* Drop collection */
            database.DropCollection("dotnet");

            /* Insert one document */
            var document = new BsonDocument
            {
                {"name", "MongoDB"},
                {"type", "database"},
                {"info", new BsonDocument
                    {{"x", 123}, {"y", 456}}
                }
            };
            Console.WriteLine("> " + document);
            collection.InsertOne(document);

            /* Insert many documents */
            var documents = Enumerable.Range(0,5).Select(i => new BsonDocument("a", i));
            foreach(var row in documents) {
                Console.WriteLine("> " + row);
            }
            collection.InsertMany(documents);
        }

        public static void FindDocuments(IMongoCollection<BsonDocument> collection) {
            Console.WriteLine("\n=== Find ===");

            /* Query all documents */
            Console.WriteLine("--- all ---");
            var docs = collection.Find(new BsonDocument()).ToEnumerable();
            foreach(var doc in docs) {
                Console.WriteLine("<< " + doc);
            }

            /* Query with filter */
            Console.WriteLine("--- with filter ---");
            var param = BsonDocument.Parse("{a: {$gt: 2}}");
            Console.WriteLine(param);
            foreach(var doc in collection.Find(param).ToEnumerable()) {
                Console.WriteLine("<< " + doc);
            }
        }

        public static void AggregateDocuments(IMongoCollection<BsonDocument> collection) {
            Console.WriteLine("\n=== Aggregate ===");

            var agg = collection.Aggregate()
                .Match(new BsonDocument { {"a", new BsonDocument {{"$gt", 0}}} })
                .Group(BsonDocument.Parse("{_id: null, total: {$sum: '$a'}, avg: {$avg: '$a'}}"));
            foreach(var doc in agg.ToEnumerable()) {
                Console.WriteLine(doc);
            }
        }

        public static void InsertObject(MongoClient client) {
            Console.WriteLine("\n=== Insert object ===");

            var database = client.GetDatabase("test");
            var collection = database.GetCollection<Person>("Persons");

            database.DropCollection("Persons");

            var person1 = new Person { Name = "John Rambo", Age = 30 };
            var person2 = new Person { Name = "Stephen Seagal", Age = 40 };
            var persons = new [] {
                new Person { Name = "Jet Li", Age = 20 },
                new Person { Name = "Chuck Norris", Age = 31 },
                new Person { Name = "John McClane", Age = 25 }
            };
            collection.InsertOne(person1);
            collection.InsertOne(person2);
            collection.InsertMany(persons);

            Console.WriteLine("--- All persons ---");
            foreach(var person in collection.Find(new BsonDocument()).ToEnumerable()) {
                Console.WriteLine("<< " + person);
            }

            Console.WriteLine("--- 30 and older ---");
            foreach(var person in collection.Find(BsonDocument.Parse("{Age: {$gte: 30}}")).ToEnumerable()) {
                Console.WriteLine("<< " + person);
            }

            Console.WriteLine("--- 30 and older (LINQ) ---");
            var query1 = from person in collection.AsQueryable()
                         where person.Age >= 30
                         select person;
            foreach(var p in query1.AsEnumerable()) {
                Console.WriteLine(p);
            }
            var query2 = collection.AsQueryable().Where(p => p.Age >= 30).Select(p => p.Age);
            Console.WriteLine("Aggregation: " + query2);
            Console.WriteLine("Total age: " + query2.Sum());
            Console.WriteLine("Avg age: " + query2.Average());
        }

        public static void Main(string[] args)
        {
            /* Connection */
            var client = new MongoClient("mongodb://localhost:27017");
            var database = client.GetDatabase("test");
            var collection = database.GetCollection<BsonDocument>("dotnet");

            MongoDotnetDriver.ListDatabases(client);
            MongoDotnetDriver.ListCollections(client);
            MongoDotnetDriver.InsertDocuments(client);
            MongoDotnetDriver.FindDocuments(collection);
            MongoDotnetDriver.AggregateDocuments(collection);
            MongoDotnetDriver.InsertObject(client);
        }
    }
}