c#mongo 2.0减少了FindAsync的流量

var filter = Builders<Book>.Filter.Eq(n => n.Author,AuthorId);

            List<String> books = new List<String>();

            using (var cursor = await BooksCollection.FindAsync(filter))
            {
                while (await cursor.MoveNextAsync())
                {
                    var batch = cursor.Current;
                    foreach (Book b in batch)
                        books.Add(b.titlE);
                }
            }

您可以通过 projection减少返回文档的大小,您可以在FindAsync的Findoptions参数中设置它,只包含您需要的字段：

var filter = Builders<Book>.Filter.Eq(n => n.Author,AuthorId);
// Just project the title and Author properties of each Book document
var projection = Builders<Book>.Projection
    .Include(b => b.titlE)
    .Include(b => b.Author)
    .Exclude("_id"); // _id is special and needs to be explicitly excluded if not needed
var options = new Findoptions<Book,BsonDocument> { Projection = projection };

List<String> books = new List<String>();

using (var cursor = await BooksCollection.FindAsync(filter,options))
{
    while (await cursor.MoveNextAsync())
    {
        var batch = cursor.Current;
        foreach (BsonDocument b in batch)
            // Get the String value of the title field of the BsonDocument
            books.Add(b["title"].AsString);
    }
}

请注意,返回的文档是BsonDocument对象而不是Book对象,因为它们只包含投影字段.