Dim tExStyle As Integer = SendMessage(TreeView1.Handle, TVM_GETEXTENDEDSTYLE, 0, 0)
    tExStyle = tExStyle Or TVS_EX_RICHTOOLTIP
    Call SendMessage(TreeView1.Handle, TVM_SETEXTENDEDSTYLE, 0, tExStyle)

  Public Const TV_FIRST = &H1100
  Public Const TVM_INSERTITEMW = (TV_FIRST + 50)
  Public Const TVM_INSERTITEM = TVM_INSERTITEMW


  <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
  Public Structure TVITEM
    Dim mask As UInteger
    Dim hItem As IntPtr
    Dim state As UInteger
    Dim stateMask As UInteger
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_PATH)> Dim pszText As String
    Dim cchTextMax As Integer
    Dim iImage As Integer
    Dim iSelectedImage As Integer
    Dim cChildren As Integer
    Dim lParam As IntPtr
  End Structure

  <StructLayout(LayoutKind.Sequential)>
  Public Structure TVINSERTSTRUCT
    Dim hParent As IntPtr
    Dim hInsertAfter As IntPtr
    Dim item As TVITEM
  End Structure

  Public Const TVI_FIRST = &HFFFF0001
  Public Const TVI_ROOT = &HFFFF0000

  ' TVITEM mask flags.
  Public Const TVIF_TEXT = &H1
  Public Const TVIF_IMAGE = &H2
  Public Const TVIF_PARAM = &H4
  Public Const TVIF_STATE = &H8
  Public Const TVIF_SELECTEDIMAGE = &H20
  Public Const TVIF_CHILDREN = &H40

  Public Declare Unicode Function SendMessage_TVINSERTSTRUCT Lib "user32" Alias "SendMessageW" _
   (ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As TVINSERTSTRUCT) As IntPtr

  Public Function TreeView_AddItem(ByVal hwndTV As IntPtr, ByVal hParent As IntPtr, ByVal hInsertAfter As IntPtr, _
   ByVal key As String, ByVal text As String, ByVal image As Integer, ByVal selectedImage As Integer) As Integer
    Dim tvi As New TVITEM
    With tvi
      .mask = TVIF_TEXT Or TVIF_IMAGE Or TVIF_SELECTEDIMAGE
      .pszText = text
      .cchTextMax = Strings.Len(text) 'MAX_PATH
      .iImage = image
      .iSelectedImage = selectedImage
    End With
    Dim tvins As New TVINSERTSTRUCT
    With tvins
      .hParent = hParent
      .hInsertAfter = hInsertAfter
      .item = tvi
    End With
    Dim hprev As IntPtr = SendMessage_TVINSERTSTRUCT(hwndTV, TVM_INSERTITEM, 0, tvins)
    MsgBox(hprev.ToString)
    Return hprev
  End Function

    TreeView_AddItem(hwndTV, IntPtr.Zero, IntPtr.Zero, "Test Item", "Test Item", 0, 0)

Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, _
 ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Public Const TV_FIRST = &H1100
Public Const TVM_INSERTITEMA = (TV_FIRST + 0)
Public Const TVM_INSERTITEM = TVM_INSERTITEMA

' TVITEM mask flags.
Public Const TVIF_TEXT = &H1
Public Const TVIF_IMAGE = &H2
Public Const TVIF_STATE = &H8
Public Const TVIF_SELECTEDIMAGE = &H20
Public Const TVIF_CHILDREN = &H40

Public Type TVITEM
  mask As Long
  hItem As Long
  state As Long
  stateMask As Long
  pszText As String 'Long    ' if a string, must be pre-allocated when struct is filled!
  cchTextMax As Long
  iImage As Long
  iSelectedImage As Long
  cChildren As Long
  lParam As Long
End Type

Public Type TVINSERTSTRUCT
    hParent As Long
    hInsertAfter As Long
    Item As TVITEM
End Type

  Public Function TreeView_AddItem(ByVal hwndTV As Long, ByVal hParent As Long, ByVal hInsertAfter As Long, _
   ByVal key As String, ByVal text As String, ByVal image As Long, ByVal selectedImage As Long) As Long
    Dim tvi As TVITEM
    With tvi
      .mask = TVIF_TEXT Or TVIF_IMAGE Or TVIF_SELECTEDIMAGE
'      .pszText = StrPtr(String$(MAX_PATH, 0))
'      Call lstrcpyA(ByVal .pszText, ByVal text)
      .pszText = text
      '.cchTextMax =  ' MAX_PATH
      .iImage = image
      .iSelectedImage = selectedImage
    End With
    Dim tvins As TVINSERTSTRUCT
    With tvins
      .hParent = hParent
      .hInsertAfter = hInsertAfter
      .Item = tvi
    End With
    Dim hprev As Long
    hprev = SendMessage(hwndTV, TVM_INSERTITEM, 0, tvins)
    MsgBox (hprev)
    TreeView_AddItem = hprev
  End Function


Dim hwndTV As Long

Private Sub Form_Load()
    hwndTV = CreateATreeView(Me.Picture1.hwnd)
     TreeView_AddItem hwndTV, 0, 0, "Мой текст As string без юникода", "Мой текст As string без юникода", 0, 0
End Sub

  Dim hwndTV As IntPtr

  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
   CreateATreeView(Me.Panel1.Handle)
    InitTreeView()
  End Sub

  Private Sub InitTreeView()
...
    'привязываем ImageList к Treeview1
    Call TreeView_SetImageList(hwndTV, m_hImlTV, TVSIL_NORMAL)
    TreeView_AddItem(hwndTV, IntPtr.Zero, IntPtr.Zero, "Test Item", "Test Item", 0, 0)
  End Sub

hwndTV = CreateATreeView(Me.Panel1.Handle)

protected override void WndProc(ref Message m) {
...
						case NativeMethods.TTN_SHOW:
                            if (WmShowToolTip(ref m))
                            {
                                m.Result = (IntPtr)1;
                                return;  
                            }
                            else
                            {
                                base.WndProc(ref m);
                                break;
                            }

Public Class TreeViewMy
  Inherits TreeView

  Protected Overrides Sub WndProc(ByRef m As Message)
    'Debug.Print(m.ToString)
    Select Case m.Msg
      Case WM_NOTIFY
        Dim nmhdr As NMHDR = CType(Marshal.PtrToStructure(m.LParam, GetType(NMHDR)), NMHDR)
        Select Case nmhdr.code
          Case TTN_SHOW
            Debug.Print("TTN_SHOW")