c# - MongoDB 和 C# Find()

Question

我有以下代码，而且我是 mongodb 的新手，我需要帮助来查找集合中的特定元素。

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
         */
  }
}
}

一旦我找到想要打印的用户，这是否可行或只会返回该位置？如果是这样，我该如何打印？

我看过一些示例 collection.Find(x => x.something) 但我不知道 x 是什么意思

Answer 1

要查找记录，您可以在 find 中使用 Lambda，例如:

var results = collection.Find(x => x.name == "system").ToList();

或者，您可以使用处理强类型 Lambda 或文本的构建器:

var filter = Builders<User>.Filter.Eq(x => x.name, "system")

或者

var filter = Builders<User>.Filter.Eq("name", "system")

然后像上面那样使用find

// 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();