Imports System.Runtime.InteropServices
 
Public Partial Class MainForm
 
	Public Const TV_FIRST = 4352
	Public Const TVSIL_NORMAL = 0
	Public Const TVSIL_STATE = 2
	Public Const TVM_SETIMAGELIST = TV_FIRST + 9
	Public Const TVM_GETNEXTITEM = TV_FIRST + 10
	Public Const TVIF_HANDLE = 16
	Public Const TVIF_STATE = 8
	Public Const TVIF_IMAGE = 2
	Public Const TVIS_STATEIMAGEMASK = 61440
	Public Const TVM_SETITEM = TV_FIRST + 13
	Public Const TVGN_ROOT = 0
    Public Const TVM_GETITEM As Integer = TV_FIRST + 62
    Public Const MY_MAXLVITEMTEXT As Integer = 260
    Private Const TVIF_TEXT As Int32 = &H1
 
	<StructLayout(LayoutKind.Sequential, Pack:=8, CharSet:=CharSet.Auto)> _
	Public Structure TVITEM
	    Dim mask As Integer
	    Dim hItem As IntPtr
	    Dim state As Integer
	    Dim stateMask As Integer
	    Dim pszText As IntPtr
	    Dim cchTextMax As Integer
	    Dim iImage As Integer
	    Dim iSelectedImage As Integer
	    Dim cChildren As Integer
	    Dim lParam As IntPtr
	End Structure
 
	<DllImport("user32.dll")> _
	Public Overloads Shared Function SendMessage _
	    (ByVal hWnd As IntPtr, ByVal Msg As Integer, _
	    ByVal wParam As Integer, ByVal lParam As Integer) As Integer
	End Function
 
	<DllImport("User32.dll", CharSet:=CharSet.Auto)> _
	Public Overloads Shared Function SendMessage _
	    (ByVal hWnd As IntPtr, ByVal msg As Integer, _
	    ByVal wParam As Integer, ByRef lParam As TVITEM) As Integer
	End Function
 
	Private Declare Function LocalAlloc _ 
	Lib "kernel32.dll" (ByVal wFlags As Int32, ByVal wBytes As Int32) As Int32
 
	Public Sub New()
		' The Me.InitializeComponent call is required for Windows Forms designer 
' support.
		Me.InitializeComponent()
		'
		' TODO : Add constructor code after InitializeComponents
		'
	End Sub
 
	Sub MainFormLoad(ByVal sender As Object, ByVal e As EventArgs)
		'// FillTreeView()	
	End Sub
 
	Sub Button1Click(ByVal sender As Object, ByVal e As EventArgs)
		Dim tvi As New TVITEM
		Dim hWnd As IntPtr = Me.treeView1.Handle 
		Dim pszText As IntPtr = IntPtr.Zero
		DIm  buffer as string = nothing
		Dim hRoot As IntPtr = IntPtr.op_Explicit(SendMessage(hWnd, TVM_GETNEXTITEM, _
  TVGN_ROOT, 0))
		tvi.hItem = hRoot
		tvi.state = 0
        SendMessage(Me.TreeView1.Handle, TVM_GETITEM, IntPtr.Zero, tvi)
        pszText = LocalAlloc(&H40, MY_MAXLVITEMTEXT)
        tvi.mask = TVIF_TEXT
		tvi.hItem = hRoot
		tvi.cchTextMax = MY_MAXLVITEMTEXT
		tvi.pszText = pszText
		SendMessage(Me.TreeView1.Handle, TVM_GETITEM, IntPtr.Zero, tvi)
		buffer = Marshal.PtrToStringUni(tvi.pszText, MY_MAXLVITEMTEXT)
        Debug.WriteLine (buffer)
		MessageBox.Show (buffer)
	End Sub
End Class