Handling 'Sequence has no elements' Exception

Question

I am updating a quantity in my cart, but it is throwing a Sequence has no elements\' exception.

And I don\'t know what that even means. At first I thought that maybe

Answer 1

You are using linq's First() method, which as per the documentation throws an InvalidOperationException if you are calling it on an empty collection.

If you expect the result of your query to be empty sometimes, you likely want to use FirstOrDefault(), which will return null if the collection is empty, instead of throwing an exception.