带三态checkbox的treeview

TriStateTreeView User Control was made to help programmer building a three state treeview. When you use this control to add node, you must use AddTreeNode method. You can get checkbox state by GetTreeNodeCheckBoxChecked method and set checkbox state by SetTreeNodeCheckBoxChecked. This control has a event:CheckBoxStateChanged occurs when the checkbox state of node changed. If you wish to change the images for checkbox, you can use CheckBoxStateImageList property to do this. Bo Xiao