Public Class frmHELP

    Private Sub InitializeTreeView()

        TreeView1.BeginUpdate()
        TreeView1.Nodes.Add("Parent")
        TreeView1.Nodes(0).Tag = "Parent.txt"

        TreeView1.Nodes(0).Nodes.Add("Child 1")
        TreeView1.Nodes(0).Nodes(0).Tag = "Child 1.txt"

        TreeView1.Nodes(0).Nodes.Add("Child 2")
        TreeView1.Nodes(0).Nodes(1).Tag = "Child 2.txt"

        TreeView1.Nodes(0).Nodes(1).Nodes.Add("Grandchild")
        TreeView1.Nodes(0).Nodes(1).Nodes(0).Tag = "Grandchild.txt"

        TreeView1.Nodes(0).Nodes(1).Nodes(0).Nodes.Add("Great Grandchild")
        TreeView1.Nodes(0).Nodes(1).Nodes(0).Nodes(0).Tag = "Great Grandchild.txt"

        TreeView1.EndUpdate()

    End Sub

    Private Sub frmHELP_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        InitializeTreeView()

    End Sub

    Private Sub TreeView1_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterSelect

        Me.RichTextBox1.LoadFile(Application.StartupPath & "\file\" & e.Node.Tag, RichTextBoxStreamType.PlainText)

    End Sub

End Class