Нажать на кнопку в диалоговом окне

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
    Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long
    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
 
    Sub нажать_на_кнопку()
 
        Dim hwnd As Long
        hwnd = FindWindow(vbNull, "Удалить файл") 'неправильный hwnd
        hwnd = FindWindowEx(hwnd, 0, "Button", "Н&ет") 'неправильный hwnd
        PostMessage(hwnd, 245, 0&, 0&) 'не работает
        PostMessage(hwnd, 245, 0&, 0&) 'не работает
 
        PostMessage(857560, 245, 0&, 0&) 'не работает даже с правильным  hwnd
        PostMessage(857560, 245, 0&, 0&) 'не работает даже с правильным  hwnd
  End Sub

  Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As UInteger
    Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As UInteger, ByVal wMsg As UInteger, ByVal wParam As UInteger, lParam As UInteger) As UInteger
    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As UInteger, ByVal hWnd2 As UInteger, ByVal lpsz1 As String, ByVal lpsz2 As String) As UInteger

Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As Integer) As Integer

hwnd = FindWindow(vbNullString, "Удалить файл")

Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long

Declare Function PostMessage& Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any)

Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As Integer) As Integer

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Integer
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, ByVal hWnd2 As Integer, ByVal lpsz1 As String, ByVal lpsz2 As String) As Integer
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Private Const BM_CLICK = 245
Private Sub tst()
    Debug.WriteLine("--Start--------------------")
    Dim hwnd As Integer = FindWindow(vbNullString, "201605test")
    Debug.WriteLine("hwnd=" & hwnd)
    Dim hwnd2 As Integer = FindWindowEx(hwnd, 0, vbNullString, "swap")
    Debug.WriteLine("hwnd2=" & hwnd2)
    Dim pp As Integer = PostMessage(hwnd2, BM_CLICK, 1, 0)
    Debug.WriteLine("pp=" & pp)
    Debug.WriteLine("--End--------------------")
End Sub

Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Integer, ByVal hWnd2 As Integer, ByVal lpsz1 As String, ByVal lpsz2 As String) As Integer
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Private Const BM_CLICK = 245
Private Sub tst()
            ' код получения хєндла окна
            Dim hwnd2 As Integer = FindWindowEx(hWnd, 0, vbNullString, "Установить")
            Debug.Print("hwnd2=" & hwnd2)
            Debug.Print("Err1==" & GetLastError.ToString)
            Dim pp As Integer = PostMessage(hwnd2, BM_CLICK, 1, 0)
            Debug.Print("Err2==" & GetLastError.ToString)
            Debug.Print("pp=" & pp)
End Sub