Tri-State TreeView control for .NET 1.1 The TreeView control as implemented by Microsoft in the .NET 1.1 Framework does support checkboxes but those checkboxes allow only two states, checked or unchecked. This control is built on top of that TreeView control and provides some additional functionality that might be useful. * Tri-State checkboxes, checked / unchecked / indeterminate states. * The TriStateTreeView supports custom images for all three states. When not using custom images, default tri-state images are provided. Custom images are configured the same way as the "ImageIndex" and the "SelectedImageIndex" properties so state images can be added to the ImageList bound to the TreeView using the ImageList property. * Checkboxes can be switched off on a per-node basis. * The TreeView recognizes two different types of TreeNodes, Containers and Items. They behave differently when child nodes are checked / unchecked.