如何在C#中使用Mongo的Aggregate框架在列表字段中累计项？

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

var client = new MongoClient("mongodb://localhost:27017");
var database = client.GetDatabase("your_database_name");
var collection = database.GetCollection<YourCollection>("your_collection_name");

var pipeline = new BsonDocument[]
{
    new BsonDocument("$unwind", "$items"),
    new BsonDocument("$group", new BsonDocument
    {
        { "_id", "$_id" },
        { "totalQuantity", new BsonDocument("$sum", "$items.quantity") }
    })
};

var result = collection.Aggregate<YourResultType>(pipeline).ToList();