Visual C++ and MFC Programming 2nd Edition

Chapter 21: Tree and List Controls Visual C++ and MFC Fundamentals

When a node has children or leaves, to show this, you

may want to display lines connecting these

relationships. To do this at design time, set the Has

Lines proeprty to True:

If you are programmatically creating the control and

you want to display lines among related nodes, add

the TVS_HASLINES style.

A node that has dependent children can display or

hides them. To display its leaves, a node must be

expanded. To hide its leaves, a node must collapse.

These operations must be obvious to the user but

something should indicate whether a node has

dependent or not. This can be illustrated by a button

that accompany such a node. To add these buttons to

the control, at design time, set the Has Buttons

property to True. This is equivalent to dynamically

creating a tree list with the TVS_HASBUTTONS

style:

Unless you have a reason to do otherwise, it is usually

a good idea to combine both the Has Buttons (or

TVS_HASBUTTONS) and the Has Lines (or

TVS_HASLINES) styles:

To show which item is the root, or which items play the roles of roots, of the tree list, you

can display a line from the root(s) to the child(ren). To do this, at design time, set the

Lines At Root property to True or add the TVS_LINESATROOT style. The line from

the root(s) to to the child(ren) can display only if the control has the Has Lines property

set to True or the TVS_HASLINES style.

When using the list, the user typically selects an item

by clicking it. If you want the mouse cursor to turn into

a pointer finger and to underline the item when the

mouse is over the node, set the Track Select property

to True or create the control with the

TVS_TRACKSELECT style.

Once the mouse pointer is on top of the desired item,

the user can click to select it.

When the user clicks another control or another application, the node that was selected

would lose its selection as the tree control would have lost focus. If you want the tree to

always show the selected item even if the control loses focus, set its Show Selection