'--------------------------------------------------------------------
'Usando SendMessage del Api de Windows, poder tener text-box con 64 KB
'en lugar de los 32 que admite Visual Basic.
'--------------------------------------------------------------------
'Declaración de la función API
'Para 16 bits usar:
Declare Function sendMessage Lib "User" (ByVal hWnd As Integer, ByVal wMsg As Integer, _
                    ByVal wParam As Integer, lParam As Any) As Long


'Para 32 bits usar:
Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, _
            ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long

'Declaración de las constantes
Global Const WM_USER = &H400
Global Const EM_LIMITTEXT = WM_USER + 21

'En el Form_Load:
Dim LTmp as long
LTmp=SendMessage(Text1.hWnd,EM_LIMITTEXT,0,byval 0&)