Dim XMLFile As String
XMLFile = "21_order_00001.xml"
 
Dim XMLDocument As XPathDocument = New XPathDocument(XMLFile)
Dim XMLNavigator As XPathNavigator = XMLDocument.CreateNavigator
 
XMLNavigator.MoveToRoot()
 
Dim XMLIterator As XPathNodeIterator = XMLNavigator.Select("//ORDER_ITEM_LIST")
 
MsgBox(XMLIterator.Count)