枚举桌面所有顶层窗口
....................\Demo
....................\....\Debug
....................\....\.....\Demo.exe
....................\....\.....\Demo.ilk
....................\....\.....\Demo.obj
....................\....\.....\Demo.pch
....................\....\.....\Demo.pdb
....................\....\.....\Demo.res
....................\....\.....\DemoDlg.obj
....................\....\.....\StdAfx.obj
....................\....\.....\vc60.idb
....................\....\.....\vc60.pdb
....................\....\Demo.cpp
....................\....\Demo.dsp
....................\....\Demo.dsw
....................\....\Demo.h
....................\....\Demo.ncb
....................\....\Demo.opt
....................\....\Demo.plg
....................\....\Demo.rc
....................\....\DemoDlg.cpp
....................\....\DemoDlg.h
....................\....\ReadMe.txt
....................\....\res
....................\....\resource.h
....................\....\...\Demo.ico
....................\....\...\Demo.rc2
....................\....\StdAfx.cpp
....................\....\StdAfx.h