Запуск стороннего приложения, отправка сообщений, получение информации с его окон

Declare Function func_name Lib "Library.dll" (parameters) As return_type;

Option Explicit
 
Private Sub Command1_Click()
On Error Resume Next
AppActivate ("Êàëüêóëÿòîð")
SendKeys ("1234567890")
End Sub

 strExpr = InputBox("Что будем считать?")
   MsgBox strExpr & " = " & Application.Evaluate(strExpr)

Declare Function FindWindow Lib "User32.dll" (lpClassName As String, lpWindowName As String) As Long;
Declare Function SendMessage Lib "User32.dll" (HWND As Long, Msg As Long, wParam As Long, lParam As Long) As Long;
Sub TryExitCalc
Const WM_CLOSE As Long = 16;
Dim W_Handle As Long;
W_Handle=FindWindow("","Калькулятор"); //получения дескриптора
SendMessage(W_Handle,WM_CLOSE,0,0);
End Sub

Option Explicit
 
Dim a As Long
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Sub TryExitCalc()
Const WM_CLOSE As Long = 16
Dim W_Handle As Long
W_Handle = FindWindow(vbNullString, "Калькулятор") 'получения дескриптора
a = SendMessage(W_Handle, WM_CLOSE, 0, 0)
End Sub
 
Private Sub Command1_Click()
Call TryExitCalc
End Sub