MongoDb c# driver 2.0 BsonNull usage

Question

I have isDeleted Nullable property in Profile class.

Builders<Profile>.Filter.Eq(p => p.IsDeleted, BsonNull.Value)

But the following code raised next compilation error:

Error 11    Cannot convert lambda expression to type 
'MongoDB.Driver.FieldDefinition<MongoDB.DataTypes.Profile,MongoDB.Bson.BsonNull>' 
because it is not a delegate type

How to implement a null-check ?

score 6 · Accepted Answer · answered Aug 07 '15 at 09:54

6

If IsDeleted is nullable, you can just use a simple null instead of BsonNull.Value when you query:

Builders<Profile>.Filter.Eq(p => p.IsDeleted, null)

answered Aug 07 '15 at 09:54

i3arnon

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How about if you want to use a different data type, like int ? – Adrian Fâciu Aug 07 '15 at 09:59
@AdrianFaciu If you want the query to by typed the value needs to be the same type as the property. So there's only a single data type possible, `bool?`. – i3arnon Aug 07 '15 at 10:00
Yes, I actually meant a different data type for the property. If the property is int. – Adrian Fâciu Aug 07 '15 at 10:01
1

@AdrianFaciu If it's a reference type, you can use `null`. If it's a value type, you need to make it a nullable one and use `null`. – i3arnon Aug 07 '15 at 10:03
Can you provide a reference on this by any chance? – KangarooWest Mar 16 '16 at 22:34
@WesternAussie on what? – i3arnon Mar 16 '16 at 23:25

MongoDb c# driver 2.0 BsonNull usage

1 Answers1