MongoDB and C# Find()
I have the below code and I am new to mongodb, I need help in finding an specific element in the collection.
using MongoDB.Bson;
using MongoDB.Driver;
namespace mongo_console {
public class User {
public ObjectId Id { get; set; }
public string name { get; set; }
public string pwd { get; set; }
}
class Program {
static void Main(string[] args)
{
MongoClient client = new MongoClient();
MongoServer server = client.GetServer();
MongoDatabase db = server.GetDatabase("Users");
MongoCollection<User> collection = db.GetCollection<User>("users");
User user = new User
{
Id = ObjectId.GenerateNewId(),
name = "admin",
pwd = "admin"
};
User user2 = new User
{
Id = ObjectId.GenerateNewId(),
name = "system",
pwd = "system"
};
collection.Save(user);
collection.Save(user2);
/*
* How do I collection.Find() for example using the name
*/
}
}
}
Once I find the user I will like to print it, is that posible or will find only return the position? if so, how do I print it?
I have seen some examples collection.Find(x => x.something) but I do not know what that x is or mean
Solution 1:
To find a record you could use Lambda in find, for example:
var results = collection.Find(x => x.name == "system").ToList();
Alternatively you can use Builders which work with strongly typed Lambda or text:
var filter = Builders<User>.Filter.Eq(x => x.name, "system")
Or
var filter = Builders<User>.Filter.Eq("name", "system")
And then use find as above
// results will be a collection of your documents matching your filter criteria
// Sync syntax
var results = collection.Find(filter).ToList();
// Async syntax
var results = await collection.Find(filter).ToListAsync();
Solution 2:
It also Varies according to the .Net framework version we are using. If we Use 2x driver it should look like :
var list = await collection.Find(new BsonDocument()).ToListAsync();
method 2
await collection.Find(new BsonDocument()).ForEachAsync(X=>Console.WriteLine(X));
Reference Example