[SyDr]

GUICtrlRead ( controlID [, advanced] )
TreeView Control identifier (controlID) of the selected TreeViewItem
TreeViewItem State of the TreeViewItem

For Treeview items several states can be returned as $GUI_FOCUS, $GUI_EXPAND and $GUI_CHECKED, $GUI_UNCHECKED (only for treeview controls with TVS_CHECKBOXES-style . So use i.e. BitAnd(GUICtrlRead($Item),$GUI_CHECKED) to test if the item is checked.