下列代码LongPtr数据类型未定义，请修改：Private Declare PtrSafe Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As LongPtr, ByVal wMsg As Long, ByVal wParam As LongPtr, lParam As Any) As LongPtr Const WM_APPCOMMAND = &H319 Const APPCOMMAND_VOLUME_UP = &HA Const APPCOMMAND_VOLUME_DOWN = &H9 Const APPCOMMAND_VOLUME_MUTE = &H8 Const HWND_BROADCAST = &HFFFF& Public Sub SetSystemVolume(ByVal level As Integer) Dim command As LongPtr command = ((level And &HFFFF&) Or ((APPCOMMAND_VOLUME_UP * &H10000) And &HFFFF0000)) SendMessage HWND_BROADCAST, WM_APPCOMMAND, 0, ByVal command End Sub Public Sub MuteSystemVolume() SendMessage HWND_BROADCAST, WM_APPCOMMAND, 0, ByVal (APPCOMMAND_VOLUME_MUTE * &H10000) End Sub

请修改代码中的LongPtr为Long。LongPtr是一个平台无关的数据类型，但只适用于64位版本的Office。如果您使用的是32位版本的Office，则需要使用Long类型。修改后的代码如下：

Private Declare PtrSafe Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Const WM_APPCOMMAND = &H319
Const APPCOMMAND_VOLUME_UP = &HA
Const APPCOMMAND_VOLUME_DOWN = &H9
Const APPCOMMAND_VOLUME_MUTE = &H8
Const HWND_BROADCAST = &HFFFF&

Public Sub SetSystemVolume(ByVal level As Integer)
Dim command As Long
command = ((level And &HFFFF&) Or ((APPCOMMAND_VOLUME_UP * &H10000) And &HFFFF0000))
SendMessage HWND_BROADCAST, WM_APPCOMMAND, 0, ByVal command
End Sub

Public Sub MuteSystemVolume()
SendMessage HWND_BROADCAST, WM_APPCOMMAND, 0, ByVal (APPCOMMAND_VOLUME_MUTE * &H10000)
End Sub