LINQ to CheckBoxList Data Elements

Question

Im using LINQ to retrieve strikethrough items from a CheckBoxList control:

Here's LINQ:

IEnumerable<int> allChecked = (from ListItem item in CheckBoxList1.Items where item.Selected select int.Parse(item.Value)); 

My question is why should the item be a ListItem type?

Answer 1

CheckedListBox was created before the introduction of generics, so the Items collection returns objects, not a strongly typed ListItem. Fortunately, fixing this with LINQ is relatively easy using OfType () (or Cast) methods:

 IEnumerable<int> allChecked = (from ListItem item in CheckBoxList1.Items.OfType<ListItem>() where item.Selected select int.Parse(item.Value)); 

Answer 2

My question is why should the item be a ListItem type?

Because CheckBoxList1.Items is an ObjectCollection of which ListItem s are ListItem . This is what your linq query works with.

Answer 3

why should the item be of type ListItem?

I think because CheckBoxList inherits from ListControl and Items property inherits from ListControl