Element 'Id' does not match any field or property of class

Question

I got the result from the collection in MongoDB, the structure is the same as below

[DataContract]
public class Father
{
    [BsonId]
    [DataMember]
    public MongoDB.Bson.ObjectId _id { get; set; }

    [DataMember]
    public string Id { get; set; }

    [DataMember]
    public List<Child> childs { get; set; }
}

[DataContract]
public class Child
{
    [DataMember]
    public string Id { get; set; }

    [DataMember]
    public int Name { get; set; }
}

When I try this:

List<Father> f = result.ToList();

It calls Element 'Id' does not match any field or property of the class Model.Child

I think it just takes 'Id' as something else.

How can I deal with it? Thank you

Can you give a more complete listing of the code that is causing this exception? For instance, what is results? Also, can you show us what the documents look like in the database (preferably in json format). — Craig Wilson, Jul 20 '12 at 13:21
I solved this problem by add a _id in the sub class as I did in the main class. I guess, all the ducument needs an 'id'.And if I don't define one , the system will think there is a '_id' in the class. That makes me couldn't transfer the document to `List`. — EasonBlack, Aug 01 '12 at 09:17
Check out the serialization options http://www.mongodb.org/display/DOCS/CSharp+Driver+Serialization+Tutorial - you can mark whatever property to be the id, it doesn't have to be '_id' for example — Alex, Nov 13 '12 at 11:23
May be related to this - https://stackoverflow.com/questions/23448634/mongodb-c-sharp-driver-ignore-fields-on-binding . — Victor Yarema, Feb 18 '19 at 17:37

score 101 · Answer 1 · edited Mar 26 '21 at 14:23

101

You can resolve the issue by adding [BsonIgnoreExtraElements] on top of the class declaration. ObjectId is internally maintained by MongoDB which may not be needed unless you want to get additional information such as timestamp from the object. Hope this helps.

edited Mar 26 '21 at 14:23

Liam

27,717
28
128
190

answered Mar 15 '19 at 15:21

Naga

2,368
3
23
33

2

this ANSWER should have been accpeted years ago. – sayo May 26 '22 at 18:52

score 12 · Answer 2 · answered Oct 21 '19 at 18:44

12

var conventionPack = new ConventionPack { new IgnoreExtraElementsConvention(true) };
        ConventionRegistry.Register("IgnoreExtraElements", conventionPack, type => true);

This works just perfectly! [BsonIgnoreExtraElements] also worked well, but, if you want to add any other ConventionRegistry like CamelCaseElementNameConvention, then, it overrides the Attribute one and the same exception occurs. Not sure if that could also be achieved using some other attribute.

answered Oct 21 '19 at 18:44

Abhilash Pokhriyal

161
1
6

Really useful if you can't add attributes to the classes – auburg Aug 18 '22 at 13:53
This is the cleanest way to do it imo. Great answer! – PNS Oct 19 '22 at 09:52

score 6 · Answer 3 · answered Nov 26 '19 at 19:21

6

I was using a dynamic list (List) to build a filter and was receiving a similar error. I added these lines to my data class to fix the problem.

[BsonId]
public ObjectId Id { get; set; }

answered Nov 26 '19 at 19:21

Tom Glenn

81
1
3

score 5 · Answer 4 · edited Mar 26 '21 at 14:26

this work for my case: add the attribute

    [DataMember]
    [BsonElement("songName")]

onto the elements:

[BsonIgnoreExtraElements]
public class Music
{
   
    [BsonId]
    [DataMember]
    public MongoDB.Bson.ObjectId _id { get; set; }
    [DataMember]
    public string Id { get; set; }

    [DataMember]
    [BsonElement("songName")]
    public string SongName { get; set; }

    [DataMember]
    [BsonElement("artistName")]
    public string ArtistName { get; set; }}

score 3 · Answer 5 · answered Jan 11 '18 at 11:59

I faced to same problem.Same error occured at var data = query.ToList();

       var collection = db.GetCollection<Product>("Products");

        var query =
            from e in collection.AsQueryable<Product>()
            where e.name == "kalem"
            select e;

        var data = query.ToList();

and my insert was this:

    var collection = db.GetCollection<Product>("Products");

    collection.InsertBatch(products);

I solved as below.

        ObjectId id = new ObjectId();
        var collection = db.GetCollection<Product>("Products");

        collection.InsertBatch(products);
        id = pr.Id;

and I added id to Product class as below Product Class

class Product
{
    public ObjectId Id { get; set; }
    public string name { get; set; }
    public string category { get; set; }
    public double price { get; set; }
    public DateTime enterTime { get; set; }
}

score 2 · Answer 6 · answered Sep 26 '22 at 14:12

2

you can use BsonNoId attribute

[DataContract]
[BsonNoId]
public class Child
{
  [DataMember]
  public string Id { get; set; }

  [DataMember]
  public int Name { get; set; }
}

answered Sep 26 '22 at 14:12

smael mahmodeyan

69
6

Nice! Thank you – Gabriel Anderson Aug 15 '23 at 21:49

score 0 · Answer 7 · answered Nov 21 '22 at 18:16

0

just add this in the top of the class [BsonIgnoreExtraElements]

answered Nov 21 '22 at 18:16

bouthayna hamdi

21
3

score -1 · Answer 8 · answered Aug 09 '16 at 13:52

all you have to do is removing the [DataMember] on the ObjecId attribute and bind the Id to the ObjectId _id.

so your class should look like this :

[DataContract]
public class Father
{
    [BsonId]
    public MongoDB.Bson.ObjectId _id { get; set; }

    [DataMember]
    public string Id { 
          get { return _id.ToString(); }
          set { _id = ObjectId.Parse(value); }
    }

    [DataMember]
    public List<Child> childs { get; set; }
}

ps : in your case the child id must be generated manually, if you want it to be an objectId(mongo), you will have do the same trick finally, to deserialized the object, you should use the newtonsoft.json reference and do like this

Father = JsonConvert.DeserializeObject<Father>(response.Content);

This actually does not work - The ObjectId.Parse(value) always returns 0's to the _id field. Better to just store this as a string IMHO — AutomationNation, Aug 23 '16 at 23:33

score -2 · Answer 9 · answered Mar 18 '13 at 22:40

Your Child class should probably specify it inherits Father

public class Child: Father { ... }

Your Father class should probably add known type attribute (for WCF ).

[DataContract]
[KnownType(typeof(Child))]
public class Father

If this is a MongoCollection("fathers") that you save / fetch through, then you may need to register a class map for each expected child type.

if (!BsonClassMap.IsClassMapRegistered(typeof(Child)))
{
    BsonClassMap.RegisterClassMap<Child>(
        cm => { cm.AutoMap(); });
}

As @alexjamesbrown mentioned, you are not required to name the id field on your poco object '_id'. The idea with inheritance is to inherit. So using the Father's "id" field (whatever it is named) should suffice. It's not clear why your Father class has both Id and _id properties. One of them is probably not necessary.

You don't need to use inheritance. I have also come across this problem. I don't know what it is yet, but I don't think it inheritance will solve it. I similar, working code, elsewhere. — Daryn, May 28 '14 at 21:02
This got me closer: http://stackoverflow.com/questions/13859295/strange-behavior-of-mongodb-linq-provider-for-fields-called-id. I eventually renamed my field to something containing more than just id or _id, both in the pocp and mongo projection. That did the trick — Daryn, May 28 '14 at 21:11

Element 'Id' does not match any field or property of class

9 Answers9

Linked