无法应对A＆＃x27; String＆＃x27;来自bsontype＆＃x27; objectid＆＃x27;

Question

我正在使用MongoDB进行ASP .NET核心项目。

我正在尝试通过酒店码来获得酒店。

hotelbedscontentservice.cs

public async Task<HotelDocument> GetHotel(int code)
        {
            var x = await HotelCollection.Find(x => x.Code == code).FirstOrDefaultAsync();
            return x;
        }

经过这条线时，我的错误低于错误。 等待_hotelbedscontentservice.gethotel（hotel.hotelcode）;

System.FormatException: An error occurred while deserializing the Destination property of class TechneTravel.Domain.Documents.HotelBedsContents.HotelDocument: An error occurred while deserializing the Id property of class TechneTravel.Domain.Documents.HotelBedsContents.DestinationDocument: Cannot deserialize a 'String' from BsonType 'ObjectId'.
 ---> System.FormatException: An error occurred while deserializing the Id property of class TechneTravel.Domain.Documents.HotelBedsContents.DestinationDocument: Cannot deserialize a 'String' from BsonType 'ObjectId'.
 ---> System.FormatException: Cannot deserialize a 'String' from BsonType 'ObjectId'.
   at MongoDB.Bson.Serialization.Serializers.StringSerializer.DeserializeValue(BsonDeserializationContext context, BsonDeserializationArgs args)
...........

hoteldocument.cs

public class HotelDocument
{
    public string Id { get; set; }
}

configuration.cs

BsonClassMap.RegisterClassMap<HotelDocument>(cm =>
            {
                cm.AutoMap();
                cm.SetIgnoreExtraElements(true);
                cm.MapIdMember(c => c.Id).SetSerializer(new StringSerializer(BsonType.ObjectId)).SetIgnoreIfDefault(true);

            });

为什么会发生此错误？我的配置有任何错误吗？

请帮助我找到问题

Answer 1

收藏集中的某些_id看起来无法转换为ObjectID。
以下代码效果很好：

        // the below is not required, but it works with that too
        //BsonClassMap.RegisterClassMap<HotelDocument>(cm =>
        //{
        //    cm.AutoMap();
        //    cm.SetIgnoreExtraElements(true);
        //    cm.MapIdMember(c => c.Id).SetSerializer(new StringSerializer(BsonType.ObjectId)).SetIgnoreIfDefault(true);
        //});

        var id = ObjectId.GenerateNewId();
        var client = new MongoClient();
        var db = client.GetDatabase("d");
        var coll = db.GetCollection<HotelDocument>("c");
        coll.InsertOne(new HotelDocument() { Id = id.ToString() });

        var result = coll.Find(c => c.Id == id.ToString()).ToList();

请提供触发您的问题的数据示例

Answer 2

MongoDB仅在ObjectID类型上插入时处理自动ID生成。

如果要使用字符串或int或长时间，则需要在插入之前设置ID。

之类的东西检查数据一致性

HashSet<BsonType> inconsistentIds = new HashSet<BsonType>();
var cursor = await collection.Find(new BsonDocument()).Project(Builders<BsonDocument>.Projection.Include("_id")).ToCursorAsync();
foreach (BsonDocument doc in cursor.ToEnumerable())
     inconsistentIds.Add(doc["_id"].BsonType);

Console.WriteLine($"There is {inconsistentIds.Count} id type");

您可以使用 https://github.com/iso8859/learn-mongodb-by-example/blob/main/main/dotnet/02%20-%20-%20-intermediate/checkidconsistency.cs