C# Treeview Control

The TreeView control contains a hierarchy of TreeViewItem controls. It provides a way to display information in a hierarchical structure by using collapsible nodes . The top level in a tree view are root nodes that can be expanded or collapsed if the nodes have child nodes.

You can explicitly define the TreeView content or a data source can provide the content. The user can expand the TreeNode by clicking the plus sign (+) button, if one is displayed next to the TreeNode, or you can expand the TreeNode by calling the TreeNode.Expand method. You can also navigate through tree views with various properties: FirstNode, LastNode, NextNode, PrevNode, NextVisibleNode, PrevVisibleNode.

The fullpath method of treeview control provides the path from root node to the selected node.

  treeView1.SelectedNode.FullPath.ToString ();

Tree nodes can optionally display check boxes. To display the check boxes, set the CheckBoxes property of the TreeView to true.

  treeView1.CheckBoxes = true;

The following C# program shows a simple demonstration of treeview control

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using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            TreeNode tNode ;
            tNode = treeView1.Nodes.Add("Websites");

            treeView1.Nodes[0].Nodes.Add("Net-informations.com");
            treeView1.Nodes[0].Nodes[0].Nodes.Add("CLR");

            treeView1.Nodes[0].Nodes.Add("Vb.net-informations.com");
            treeView1.Nodes[0].Nodes[1].Nodes.Add("String Tutorial");
            treeView1.Nodes[0].Nodes[1].Nodes.Add("Excel Tutorial");

            treeView1.Nodes[0].Nodes.Add("Csharp.net-informations.com");
            treeView1.Nodes[0].Nodes[2].Nodes.Add("ADO.NET");
            treeView1.Nodes[0].Nodes[2].Nodes[0].Nodes.Add("Dataset");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show(treeView1.SelectedNode.FullPath.ToString ());
        }
    }
}