Question

I’m generating two IEnumerable<int> objects:

var listA = model.SelectedFormats.Select(a => a.ID); //values: 1,2,4
var listB = basket.OrderPosition.Select(x => x.BookFormatTypeID); //values: 1,4


var result = listA.Except(listB);

but I can’t see any results from the Except method (the compiler doesn’t show even that the
result is)

Answer 1

IEnumerable.Except() does not return elements directly, it returns an IEnumerable which you can access to iterate over the result.

You could change the last line to

#if DEBUG
    List<myResultType> result = new List<myResultType>(listA.Except(listB));
#else
    var result = listA.Except(listB);
#endif

This would automatically iterate over the elements and add them to a list, allowing you to inspect the result.