Visual FoxPro 6.0 Sample: Demonstrates the TreeView Control (253454)

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The following file is available for download from the Microsoft Download Center:
Release Date: May-24-2000

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The TreeView.exe file contains the following files:

File Name	Size
ReadMe.txt	3,323
TreeView.pjx	2,363
TreeView.pjt	4,554
TreeView.scx	8,990
TreeView.sct	61,528
AddNode.scx	3,431
AddNode.sct	13,705
Closed.bmp	222
Happy.bmp	382
Leaf.bmp	222
Minus.bmp	222
Open.bmp	222
Plus.bmp	222

A tree view is a way of presenting information in a hierarchical format that looks like an upside-down tree. Like branches on a tree, the tree view has branches of information that start from a root point. Individual points on the tree stop at a leaf or split to form more branches or leaves. Each one of these points on the tree is referred to as a node. A node can be a final point on a branch or it can have its own set of nodes, called child nodes. Nodes that have child nodes are referred to as parent nodes. The nodes located at the very top of the tree view are referred to as root nodes. Root nodes do not have parent nodes, but they can have sibling nodes (nodes located on the same branch).

The TreeView control contains, organizes, and presents Node objects in a tree view. A Node object contains an index, key value, and text (or label). You must specify a key value and text for the node. The key value must be a unique value for that node in the collection. The index is created when you add a node to the collection. If you want, you may include an ImageList control on the form containing the TreeView control to specify images that may be used by TreeView. This allows you to specify a default image, selected image, or an expanded image for each node. The selected image appears for a node while that node in TreeView has the focus. The expanded image appears when a parent node has been expanded so that its child nodes are visible in TreeView.

The first node added to a tree view is a root node. Each node added after that may be another root node or a node that has a relationship to a node that has already been added. If you are adding a node that has a relationship, you are required to specify the key value of the node to which the new node is related and the relationship to that node. There are five types of relationships that you may specify for a new node:

• Child - this creates the new node as a child node for the related node.
  
  The following four relationship types create sibling nodes for the related node and allow you to specify where the new node is placed in relationship to the related node:
  
  
• First
• Last
• Next
• Previous
  
  The default relationship is Next.

This example contains a project (TreeView) that contains two forms (TreeView, AddNode) and six bitmap (.bmp) files. The TreeView form contains TreeView as well as other controls that allow you to manipulate or view the properties of the TreeView form as well as the currently selected node in TreeView. There are ToolTips that help explain the purpose of the property that is being controlled or displayed. There are also command buttons that contain code so that you may see how to build the Nodes collection of TreeView, expand and collapse all the nodes in the TreeView, plus add and remove nodes from the TreeView. There is also an ImageList control so that you can see how to include images on the TreeView. The second form (AddNode) provides a user interface to add nodes to the TreeView. This allows you to try the five different types of relationships for the new node.