MongoDB C# Driver - Ignore fields on binding

Question

When using a FindOne() using MongoDB and C#, is there a way to ignore fields not found in the object?

EG, example model.

public class UserModel
{
           


        

Answer 1

Yet Another possible solution, is to register a convention for this.

This way, we do not have to annotate all classes with [BsonIgnoreExtraElements].

Somewhere when creating the mongo client, setup the following:

        var pack = new ConventionPack();
        pack.Add(new IgnoreExtraElementsConvention(true));
        ConventionRegistry.Register("My Solution Conventions", pack, t => true);

Answer 2

Yes. Another way (instead of editing you model class) is to use RegisterClassMap with SetIgnoreExtraElements.

In your case just add this code when you initialize your driver:

BsonClassMap.RegisterClassMap<UserModel>(cm =>
{
     cm.AutoMap();
     cm.SetIgnoreExtraElements(true);
});

You can read more about ignoring extra elements using class mapping here - Ignoring Extra Elements.

Answer 3

Yes. Just decorate your UserModel class with the BsonIgnoreExtraElements attribute:

[BsonIgnoreExtraElements]
public class UserModel
{
    public ObjectId id { get; set; }
    public string Email { get; set; }
}

As the name suggests, the driver would ignore any extra fields instead of throwing an exception. More information here - Ignoring Extra Elements.