Returns a container for testing controls within the repeater's ItemTemplate and AlternatingItemTemplate. The 'itemNum' is the item to look for. itemNum zero is the first instance of ItemTemplate; itemNum one is the second instance of ItemTemplate, or AlternatingItemTemplate if it's in use; etc. This method does NOT check to see if the repeater is visible or if the item number is legal on the current page. Instead, you'll get a NotVisibleException when you attempt to use the tester instantiated with the result of this method.
A container tester for the requested item