如何从MongoDB读取

Question

我正在尝试使用以下代码从MongoDB中读取一行

public static void MongoConnection()
{
    var connectionString = "127.0.0.1";

    var mongoClient = new MongoClient(connectionString);

    var mongoServer = mongoClient.GetServer();

    var databaseName = "PointToPoint";
    var db = mongoServer.GetDatabase(databaseName);
    var mongodb = db.GetCollection("OCS.MeterEntity");

    BsonDocument documentRead = mongodb.FindOne(new QueryDocument {
    {"_id", "4B414D000000011613CD" }
});

但是documentRead始终为null，我知道指定的_id存在于数据库中。 我究竟做错了什么？

它确实连接到数据库和正确的表。

Answer 1

似乎是一个调用约定：

new QueryDocument( "_id", new ObjectId("4B414D000000011613CD") )

但这也应该起作用：

new BSONDocument { { "_id", "4B414D000000011613CD" } }

Answer 2

我努力弄清楚:)

public static void MongoConnection()
        {
            var connectionString = "mongodb://localhost";
            var mongoClient = new MongoClient(connectionString);
            var mongoServer = mongoClient.GetServer();
            var databaseName = "PointToPoint";
            var db = mongoServer.GetDatabase(databaseName);
            var mongodb = db.GetCollection<MongoDBModel>("OCS.MeterEntity");
            var mongodbQuery = Query<MongoDBModel>.EQ(x => x._id, "4B414D000000011613CD");
            var foundMongoDB = mongodb.FindOne(mongodbQuery);
        }