The image index that is returned by this property is contained in the StateImageList property of the parent TreeView control.
If the parent TreeView has check boxes enabled, the StateImageIndex is ignored and the node will display the first or second image in the StateImageList set on the parent TreeView to indicate an unchecked or checked state, respectively. Toggling the Checked property does not affect the value of the StateImageIndex.
The StateImageIndex returns -1 when not set. The StateImageKey and StateImageIndex properties are mutually exclusive, meaning if one is set, the other is ignored. If you set the StateImageKey property, the StateImageIndex property is automatically set to -1. Alternatively, if you set StateImageIndex, StateImageKey is automatically set to an empty string ("").
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)