怎样等待一个SHELL调用程序执行完再继续

Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredaccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Const INFINITE = -1&
Private Const SYNCHRONIZE = &H100000

Private Sub Command1_Click()
Dim i As Long
Dim r As Long
Dim p As Long
i = Shell("notepad.exe", vbNormalFocus)
p = OpenProcess(SYNCHRONIZE, False, i)
r = WaitForSingleObject(p, INFINITE)
r = CloseHandle(p)
MsgBox "记事本已经关闭"
End Sub