Obtener el valor de un textbox desde otra aplicación

[boluart]

Haber abre un Form agregale 1 Boton y 1 ListBox, al ListBox agregale al menos 1 elemento

Código:

 
Option Explicit
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Integer, ByVal lParam As Any) As Long
Private Sub Command1_Click()
    Dim Wnd4, R4 As Long
    Const LB_ADDSTRING As Long = 384
    Const LB_GETCOUNT As Long = 395
    Const LB_DELETESTRING As Long = 386
    Const LB_GETTEXT  As Long = 393
    Dim cad As String
    cad = "         "
    Wnd4 = Me.List1.hwnd
    R4 = SendMessage(Wnd4, LB_GETTEXT, 0, cad)
    MsgBox cad
End Sub