VB.NET TreeView Control

The TreeView control is used to display a hierarchical representation of the same data in a tree structure. The top-level in the tree view is the root node with one or more child nodes. In addition, the root node can be contracted or expanded by clicking on the plus sign (+) button. It is also useful to provide the full path of the root node to the child node.

Let's create a TreeView control in the VB.NET Windows form using the following steps.

Step : We have to find the TreeView control from the toolbox and then drag and drop the TreeView control onto the window form, as shown below.

Step 2: Once the TreeView is added to the form, we can set various properties of the TreeView by clicking on the TreeView control.

Properties of the TreeView Control

There are following properties of the TreeView control.

Properties	Description
Nodes	The nodes property of the tree view control is used to gather all the nodes used in the tree.
SelectedNode	It is used to obtain or set the tree node that is selected in the tree view control.
ShowRootLines	It gets or sets a value that represents whether you want to draw lines between the tree nodes connected with the root of the tree view.
Path Separator	The Path Separator property of the Tree View Control is used to set a delimiter string between the tree node paths.
ShowPlusMinus	It is used to get or set a value representing whether you want to display the plus (+) or minus sign button next to tree nodes containing the child nodes.
ShowLines	It takes a value representing whether you want to draw lines between the tree nodes of the tree view control.
TopNode	It is used to get or set full visible tree nodes on top of other nodes in the tree view control.
VisibleCount	It is used to obtain the fully visible tree node in the tree view control.
ItemHeight	The ItemHeight property is used to set the height of each tree node in control.
Scrollable	The Scrollable property is used in the tree-view to display the scroll bar by setting the value in control.

Methods of the TreeView Control

Method	Description
GetNodeAt	A GetNodeAt() method is used to get a node at the specified location of the tree view control.
Sort()	A Sort method is used to sort the tree nodes that are available in the tree view control.
ExpandAll()	As the name suggests, an ExpandAll method is used to expand all the tree nodes.
GetNodeCount	It is used to count the number of nodes that are available in the tree view control.
CollapseAll	It is used to collapse all tree nodes, including all child nodes in the tree view control.
ToString	ToString method is used to return the name of the string that is in the tree view control.

Furthermore, we can also refer to VB.NET Microsoft documentation to get a complete list of TreeView control properties and methods.

Let's create a program to insert a node in the tree view control of the VB.NET form.

treeView.vb

Public Class treeView
    Private Sub treeView_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Text = "javaTpoint.com" 'Set the title name for the Windows form.
        Button1.Text = "Add New Node" 'Set the name of button
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim nd As String
        nd = InputBox("Enter Node name")  ' takes input from the user
        If TreeView1.SelectedNode Is Nothing Then  ' insert a new node.
            TreeView1.Nodes.Add(nd, nd)
        Else
            TreeView1.SelectedNode.Nodes.Add(nd, nd)   ' insert into the sub node or child node
        End If
    End Sub
End Class

Output: