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Public Const LOCALE_STIMEFORMAT = &H1003
Public Const LOCALE_SSHORTDATE = &H1F
Public Const WM_SETTINGCHANGE = &H1A
  Public Const HWND_BROADCAST = &HFFFF&
  Const SPI_SETDESKWALLPAPER = 20
  Const SPIF_SENDCHANGE = &H2
Public Declare Function SetLocaleInfo Lib "kernel32" Alias "SetLocaleInfoA" (ByVal Locale As Long, ByVal LCType As Long, ByVal lpLCData As String) As Boolean
Public Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Function GetSystemDefaultLCID Lib "kernel32" () As Long
Public Declare Function GetLocaleInfo Lib "kernel32" Alias "GetLocaleInfoA" (ByVal Locale As Long, ByVal LCType As Long, ByVal lpLCData As String, ByVal cchData As Long) As Long
Public Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByVal lpvParam As Any, ByVal fuWinIni As Long) As Long

  Public Sub setdateformat()
    Dim dwLCID     As Long, i       As Long
    Dim lpLCData     As String * 255, cchData
    cchData = Len(lpLCData)
        dwLCID = GetSystemDefaultLCID()
    i = SetLocaleInfo(dwLCID, LOCALE_STIMEFORMAT, "h:mm:ss") '设置时间格式
    PostMessage HWND_BROADCAST, WM_SETTINGCHANGE, 0, 0
    SystemParametersInfo SPI_SETDESKWALLPAPER, 0, "", SPIF_SENDCHANGE
    Debug.Print Time
  End Sub

然后，在相应的窗口代码中调用setdateformat即可。

缺点：改好相应的格式（如"h:mm:ss”，需重新启动或注销系统再次打开程序方生效）