Top view of binary tree using recursion in vb.net

Vb program for Top view of binary tree using recursion. Here problem description and other solutions.

' Include namespace system
Imports System 
'  Vb.net program for
'  Top view of binary tree using dfs

'  Binary Tree Node
Public Class TreeNode 
    Public  data As Integer
    Public  left As TreeNode
    Public  right As TreeNode
    
    Public Sub New(ByVal data As Integer)
        '  Set node value
        Me.data = data
        Me.left = Nothing
        Me.right = Nothing
    
    End Sub

End Class
public Class BinaryTree 
    Public  root As TreeNode
    Public  level As Integer
    
    Public Sub New()
        '  Set the initial value of root
        Me.root = Nothing
        Me.level = 0
    End Sub
    
    '  Print left side top nodes including root
    Public Sub printleftSide(ByVal node As TreeNode, 
                             ByVal depth As Integer)
        if (node IsNot Nothing) Then 
            if (Me.level < depth) Then 
                '  Print the resultant node
                Console.Write("  " + node.data.ToString())
                Me.level = depth
            End If

            '  Recursively
            '  Visit left subtree
            Me.printleftSide(node.left, depth + 1)
            '  Visit right subtree
            Me.printleftSide(node.right, depth - 1)
        End If

    
    End Sub
    '  Print right side top nodes
    
    Public Sub printRightSide(ByVal node As TreeNode, 
                              ByVal depth As Integer)
        if (node IsNot Nothing) Then 
            if (Me.level < depth) Then 
                '  Print the resultant node
                Console.Write("  " + node.data.ToString())
                Me.level = depth
            End If

            '  Recursively
            '  First visit right subtree
            Me.printRightSide(node.right, depth + 1)
            '  Then
            '  Visit left subtree
            Me.printRightSide(node.left, depth - 1)
        End If

    
    End Sub
    '  This is handle the request of printing top view
    
    Public Sub topView()
        Me.level = -1
        Me.printleftSide(Me.root, 0)
        Me.level = 0
        Me.printRightSide(Me.root, 0)
    
    End Sub
    
    Public Shared Sub Main(ByVal args As String())
        '  Create new tree
        Dim tree As BinaryTree = New BinaryTree()
        '   Make A Binary Tree
        '-----------------------
        '         1
        '       /   \
        '      2     3
        '     /     / \
        '    4     5   6
        '   /       \    
        '  7         8    
        '             \
        '              9
        '               \
        '                10
        '  Construct binary tree
        tree.root = New TreeNode(1)
        tree.root.left = New TreeNode(2)
        tree.root.right = New TreeNode(3)
        tree.root.right.right = New TreeNode(6)
        tree.root.right.left = New TreeNode(5)
        tree.root.left.left = New TreeNode(4)
        tree.root.left.left.left = New TreeNode(7)
        tree.root.right.left.right = New TreeNode(8)
        tree.root.right.left.right.right = New TreeNode(9)
        tree.root.right.left.right.right.right = New TreeNode(10)
        '  Display top view
        tree.topView()
    
    End Sub

End Class

Output

  1  2  4  7  3  6  10