MongoDB .Net -筛选数组子数组中的项目

db.collection.aggregate([
  {
    $project: {
      filteredArray: {
        $filter: {
          input: "$arrayField", // 数组字段名
          as: "item", // 数组元素的别名
          cond: {
            $gte: ["$$item.field", 10] // 筛选条件，此处为大于等于10
          }
        }
      }
    }
  }
])

using MongoDB.Bson;
using MongoDB.Driver;

var collection = database.GetCollection<BsonDocument>("collectionName");

var pipeline = new BsonDocument[]
{
    new BsonDocument("$project", new BsonDocument
    {
        { "filteredArray", new BsonDocument
            {
                { "$filter", new BsonDocument
                    {
                        { "input", "$arrayField" },
                        { "as", "item" },
                        { "cond", new BsonDocument
                            {
                                { "$gte", new BsonArray { "$$item.field", 10 } }
                            }
                        }
                    }
                }
            }
        }
    })
};

var result = collection.Aggregate(pipeline).ToList();