How to enumerate the Item in ListView?

How to Enumerate All Items of the ListView Control in the script dialog?

How to get the number of items for the ListView control?

Control.Count and Control.GetItemAt: https://www.gpsoft.com.au/help/opus12/index.html#!Documents/Scripting/Control.htm

how to get a items collection?

AddItem Method be should return a DialogListItem object.
Add an Items attribute to Control object, return a collection.

Maybe have a look at my listview sample code i posted on a different topic here

That would make adding multiple items slower.

You can get the item you added via other methods when you need it.