<System.Runtime.InteropServices.DllImport("user32.dll", _
        EntryPoint:="SendMessage")> _
Public Shared Function SendMessage(ByVal hWnd As System.IntPtr, _
        ByVal Msg As Integer, ByVal uParam As Integer, _
        ByVal lparam As System.Text.StringBuilder) As Integer
End Function

   Dim picturebox1 As New PictureBox
   Dim buffersize As Integer = CInt(2 ^ 15)
   Dim Text As New System.Text.StringBuilder(buffersize)
   Dim ret1 As Integer = _
        SendMessage(picturebox1.Handle, &HE, buffersize, Text)
 
   Dim str As String = String.Empty
   If ret1 > 0 Then
      Dim ret As Integer = _
      SendMessage(picturebox1.Handle, &HD, buffersize, Text)
      If ret > 0 Then
         str = Text.ToString
      End If
   End If