Insert element into nested array in Mongodb

Question

I have this :

{
  \"_id\" : ObjectId(\"4fb4fd04b748611ca8da0d48\"),
  \"Name\" : \"Categories\",
  \"categories\" : [{
      \"_id\" : ObjectId(\"4fb4fd04b74         


        

Answer 1

You can use the positional operator using Linq expressions too:

public async Task Add(string productId, string categoryId, SubCategory newSubCategory)
{
    var filter = Builders.Filter.And(
         Builders.Filter.Where(x => x.Id == productId), 
         Builders.Filter.ElemMatch(x => x.Categories, c => c.Id == categoryId));
    var update = Builders.Update.Push(x => x.Categories[-1].SubCategories, newSubCategory);
    await collection.FindOneAndUpdateAsync(filter, update);
}

And get yourself free of using hard-coded property names inside strings.