Add Group Collapse Behavior on a Listview Control
Introduction
ListView control is an important but complex control in the  WinForm environment. Group behavior is added into this control, but  unfortunately, we can't collapse or expand the group. 
I'll show how to use some simple code to add collapse/expand behavior on the  ListView control. 
This is a sample image on Windows Vista and Windows Server 2008:
 
 
Default group without Collapse/Expand behavior
  
 
Group with Collapse/Expand behavior
  
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