Question

I need to select User Name from the collection of Users. I do it in a such way:

MongoCollection<Enums> coll = Db.GetCollection<Enums>("Users"); 
var query = Query.EQ("_id", id); 
var res = coll.FindOne(query); 
var name = res.Name; 
var url = res.UserUrl; //or some more fields, not just Name

Assuming that User document can contain a lot of data, and there is no need to transfer the whole user document, how to select only a few distinct fields, using official C# driver?

Answer 1

You’ll have to use a function that returns a MongoCursor.
In the MongoCursor you can specify the fields you want to return.

var result = Db.GetCollection<Enums>("Users").FindAll();
result.Fields = Fields.Include(new [] {"Name"});;

foreach (var user in result)
{   
    Console.WriteLine(user.Name);
}