1、打开Excel，ALT+F11进入VBA，新建一个模块，输入关于定时器的代码，如下：
Public Declare PtrSafe Function SetTimer Lib "user(这里连起来)32" ( _
ByVal HWnd As Long, _
ByVal nIDEvent As Long, _
ByVal uElapse As Long, _
ByVal lpTimerFunc As LongPtr) As Long
Public Declare PtrSafe Function KillTimer Lib "user(这里连起来)32" ( _
ByVal HWnd As Long, _
ByVal nIDEvent As Long) As Long
Public TimerID As Long
Public TimerSeconds As Single
Sub StartTimer()
TimerSeconds = 1
TimerID = SetTimer(0&, 0&, TimerSeconds * 1000&, AddressOf TimerProc)
End Sub
Sub EndTimer()
On Error Resume Next
KillTimer 0&, TimerID
End Sub
Sub TimerProc(ByVal HWnd As Long, ByVal uMsg As Long, _
ByVal nIDEvent As Long, ByVal dwTimer As Long)
UserForm1.TextBox1.Text = Now()
End Sub
2、新建窗体UserForm1，在窗体上拖入一个文本框和一个按钮
3、双击窗体上的按钮，进入按钮的点击事件，调用定时器的启动函数：StartTimer
4、在窗体的退出添加事件，关闭定时器：EndTimer
