Dynamic Treeview in VB.NET

Write a program to create a Treeview dynamically with buttons Add To Root, Add To Selected Node, Remove and Scan buttons.On click of Scan button all the nodes of the Treeview should be listed in the Listbox placed in side by.

CODING

Public Class Form1
    Dim tnode As New TreeNode
    Private Sub AddNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles AddNodesToolStripMenuItem.Click
        If TextBox1.Text = "" Then
            MsgBox("Enter Node Name in Right side Box")
        Else
            TreeView1.Nodes.Add(TextBox1.Text)
        End If
    End Sub
    Private Sub SelectedNodeToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SelectedNodeToolStripMenuItem.Click
        If TextBox1.Text = "" Then
            MsgBox("Enter Node Name in Right side Box")
        ElseIf TreeView1.SelectedNode Is Nothing Then
            MsgBox("Select A Node")
        Else
            TreeView1.SelectedNode.Nodes.Add(TextBox1.Text)
        End If
    End Sub
    Private Sub CountAllNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles CountAllNodesToolStripMenuItem.Click
        MsgBox("Total Nodes " & TreeView1.Nodes.Count)
    End Sub
    Private Sub SelectedNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SelectedNodesToolStripMenuItem.Click
        If TreeView1.SelectedNode Is Nothing Then
            MsgBox("Select A Node")
        Else
            MsgBox("Total Nodes " & TreeView1.SelectedNode.Nodes.Count)
        End If
    End Sub
    Private Sub RemoveAllNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles RemoveAllNodesToolStripMenuItem.Click
        TreeView1.Nodes.Clear()
    End Sub
    Private Sub RemoveSelectedNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles RemoveSelectedNodesToolStripMenuItem.Click
        If TreeView1.SelectedNode Is Nothing Then
            MsgBox("Select A Node")
        Else
            TreeView1.SelectedNode.Remove()
        End If
    End Sub
    Private Sub ExpandAllNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ExpandAllNodesToolStripMenuItem.Click
        TreeView1.ExpandAll()
    End Sub
    Private Sub ExpandSelectedNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ExpandSelectedNodesToolStripMenuItem.Click
        If TreeView1.SelectedNode Is Nothing Then
            MsgBox("Select A Node")
        Else
            TreeView1.SelectedNode.Expand()
        End If
    End Sub
    Private Sub CollpaseAllNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles CollpaseAllNodesToolStripMenuItem.Click
        TreeView1.CollapseAll()
    End Sub
    Private Sub CollpaseSelectedNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles CollpaseSelectedNodesToolStripMenuItem.Click
        If TreeView1.SelectedNode Is Nothing Then
            MsgBox("Select A Node")
        Else
            TreeView1.SelectedNode.Collapse()
        End If
    End Sub
    Private Sub ScanneAllNodesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ScanneAllNodesToolStripMenuItem.Click
        For Each tnode In TreeView1.Nodes
            Call scann_node(tnode)
        Next
    End Sub
    Sub scann_node(ByVal tnode As TreeNode)
        Static indentlevel As Integer
        Application.DoEvents()
        ListBox1.Items.Add(Space(indentlevel) & tnode.Text)
        If tnode.Nodes.Count > 0 Then
            indentlevel += 5
            For Each tnode In tnode.Nodes
                scann_node(tnode)
            Next
            indentlevel -= 5
        End If
    End Sub
End Class

DESIGNING