Freetutes.com

VB6 beginners tutorial - Learn VB6

Advanced VB6 tutorial - Learn Advanced VB6

VB .NET - Learn Visual Basic .NET

Systems Analysis - System analysis and Design tutorial for Software Engineering


You are here: Visual Basic > Advanced VB6 tutorial > Chapter 4

VB TreeView Control - Add and Remove Methods (Visual Basic 6)

Nodes can be added to the TreeView control by using the Add method of the Nodes Collection. The syntax for Add is as follows:

TreeView1.Nodes.Add(relative, relationship, key, text, image, selectedimage)

All the arguments for the Add method are optional. The Relative argument gives VB the Key or Index of an existing node, and the Relationship parameter tells VB where to place the new node in relation to the relative node. If the Relative and relationship arguments are not specified, the new node will be placed at the top level in the tree after all other existing nodes at that level.

The values for the relationship argument are as follows:

  • tvwFirst (0) The new node is placed at the same level in the tree as the "relative." It will be added as the first node of that level.
  • tvwLast (1) The new node is placed at the same level in the tree as the "relative" but will be added after the last existing node at the same level as "relative."
  • tvwNext (2) The new node will be placed at the same level in the tree as the "relative," immediately following that node.
  • tvwPrevious (3) The new node will be placed at the same level in the tree as the "relative," immediately preceding that node.
  • tvwChild (4) The new node will be a child of the "relative" node.

The Key property identifies the new node in the tree. If provided as an argument, it must be a unique string, not used as a key by any other node in the tree. The key is used to retrieve or to find this node when the index is not known.

The last three arguments of the Add method define the appearance of the new node. The text that appears next to a node in the TreeView is specified by the Text argument, a string value. If you want to have icons appear in the TreeView alongside the Text, you must first have an ImageList control on your form. When you set up a TreeView and define its properties through the Property Pages dialog box, you can bind an ImageList to the TreeView . Figure 4.5 shows an example of this.

Binding an ImageList to a TreeView control.
FIGURE 4.5 Binding an ImageList to a TreeView control.

To include an icon with the node text, you can use the Image argument. This argument has an integer value that corresponds to the index of an image in the bound ImageList control. The ImageList has to be set up first so that the index values are available for use in the TreeView control. If you want a node to have a different icon displayed when that node is selected by the user, you can specify a second icon with the SelectedImage argument. This is also an integer argument identifying an image in the same ImageList.

Treeview Control topics

See Also


  

.<< Previous | Contents | Next >>

Home | About Us | Privacy Policy | Contact Us

Copyright © Freetutes.com | All Rights Reserved