I follow an example on the book but got errors.
Thanks for help
Code:
Error	1	Value of type 'System.Windows.Forms.TreeNode' cannot be converted to 'System.Windows.Forms.TreeView'.	
Error	2	Name 'directoryArray' is not declared.
FrmListBox

Code:
Imports System.Windows.Forms
Imports System.IO
Public Class Form1

    Friend WithEvents trdDirectory As TreeView
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        trdDirectory.Nodes.Add("C:")
        PopulateTreeView("C:\", trdDirectory.Nodes(0)) ' error 1 here
    End Sub

    Private Sub PopulateTreeView(ByVal directoryValue As String, ByVal parentNode As TreeView)
        Try
            Dim treDirectory As String() = Directory.GetDirectories(directoryValue)

            If directoryArray.Length <> 0 Then  'error 2 here
                Dim currentDirectory As String
                For Each currentDirectory In directoryArray
                    Dim myNode As TreeNode = New TreeNode(currentDirectory)
                    parentNode.Nodes.Add(myNode)
                    PopulateTreeView(currentDirectory, myNode)

                Next
            End If
        Catch unauthorized As UnauthorizedAccessException
            parentNode.Nodes.Add("Access Denied")
        End Try
    End Sub
End Class