Case WM_DRAWITEM
      'Debug.Print "WM_DRAWITEM"
      Call CopyMemory(dm, ByVal lParam, Len(dm))
      If dm.CtlType = ODT_MENU Then

  Private Structure RECT
    Public Left As Integer
    Public Top As Integer
    Public Right As Integer
    Public Bottom As Integer
  End Structure

  ' DRAWITEMSTRUCT for ownerdraw
  Private Structure DRAWITEMSTRUCT
    Public CtlType As Integer
    Public CtlID As Integer
    Public itemID As Integer
    Public itemAction As Integer
    Public itemState As Integer
    Public hwndItem As IntPtr
    Public hdc As IntPtr
    Public rcItem As RECT
    Public itemData As IntPtr
  End Structure

 Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
...
    Dim dm As DRAWITEMSTRUCT
...
    Select Case m.Msg
...
      Case WM_DRAWITEM 
        Debug.WriteLine("WM_DRAWITEM")
        dm =   'надо m.LParam -> DRAWITEMSTRUCT

Private Structure 
 Public CtlType as... 

Private Type
   CtlType as... 

Imports System.Runtime.InteropServices

      Case WM_DRAWITEM 
        Debug.WriteLine("WM_DRAWITEM")
        dm = CType(Marshal.PtrToStructure(m.LParam, GetType(DRAWITEMSTRUCT)),  _
         DRAWITEMSTRUCT)
        If dm.CtlType = ODT_MENU Then
          Debug.WriteLine("ODT_MENU")
        End If