请问如何用代码实现timer的功能，比如一秒之后raise一个event?

2003-10-25 11:19:42 55 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

UEFI源码解析之EVENT UEFI-EDK2是单核单线程的架构，除了时钟中断外，没有其他中断机制，Event在UEFI中实现了异步执行的能力；阅读详情

请问如何用代码实现timer的功能，比如一秒之后raise一个event?

最好是消耗资源小一点的。如果是设一个循环，不断的取当前时间，直到与开始时间相差一秒就raise event，这样的消耗就大了点。

不知道有没有什么api或者其它什么办法可以实现这个功能吗？当然，要不用控件的。

...全文

低精度定时器 (timer_list) 和高精度定时器 (hrtimer) Linux内核提供两种定时器：低精度(timer_list)和高精度(hrtimer)。timer_list基于jiffies实现毫秒级精度，适合简单任务，通过timer_setup初始化和mod_timer启动。hrtimer提供纳秒级精度，适用于实时系统，使用hrtimer_init初始化和hrtimer_start启动。两种定时器都需要正确设置回调函数并在模块卸载时取消定时器。示例代码展示了5秒低精度定时器和500微秒高精度定时器的实现方法，包括初始化、设置和清理流程。阅读详情

leoxue

VB基础类 7,788 成员 197,583 内容

+ 关注 + 加入社区

切换为时间正序

rainstormmaster 2003-10-25

打赏
举报

模块：
Public Const DT_CENTER = &H1
Public Const DT_WORDBREAK = &H10
Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type
Declare Function DrawTextEx Lib "user32" Alias "DrawTextExA" (ByVal hDC As Long, ByVal lpsz As String, ByVal n As Long, lpRect As RECT, ByVal un As Long, ByVal lpDrawTextParams As Any) As Long
Declare Function SetTimer Lib "user32" (ByVal hwnd As Long, ByVal nIDEvent As Long, ByVal uElapse As Long, ByVal lpTimerFunc As Long) As Long
Declare Function KillTimer Lib "user32" (ByVal hwnd As Long, ByVal nIDEvent As Long) As Long
Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Long) As Integer
Declare Function SetRect Lib "user32" (lpRect As RECT, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Global Cnt As Long, sSave As String, sOld As String, Ret As String
Dim Tel As Long
Function GetPressedKey() As String
For Cnt = 32 To 128
'Get the keystate of a specified key
If GetAsyncKeyState(Cnt) <> 0 Then
GetPressedKey = Chr$(Cnt)
Exit For
End If
Next Cnt
End Function
Sub TimerProc(ByVal hwnd As Long, ByVal nIDEvent As Long, ByVal uElapse As Long, ByVal lpTimerFunc As Long)
Ret = GetPressedKey
If Ret <> sOld Then
sOld = Ret
sSave = sSave + sOld
End If
End Sub

窗体：
Private Sub Form_Load()
Me.Caption = "Key Spy"
'启动定时器，1000毫秒触发一次
SetTimer Me.hwnd, 0, 1000, AddressOf TimerProc
End Sub
Private Sub Form_Paint()
Dim R As RECT
Const mStr = "Start this project, go to another application, type something, switch back to this application and unload the form. If you unload the form, a messagebox with all the typed keys will be shown."
'Clear the form
Me.Cls
'API uses pixels
Me.ScaleMode = vbPixels
'Set the rectangle's values
SetRect R, 0, 0, Me.ScaleWidth, Me.ScaleHeight
'Draw the text on the form
DrawTextEx Me.hDC, mStr, Len(mStr), R, DT_WORDBREAK Or DT_CENTER, ByVal 0&
End Sub
Private Sub Form_Resize()
Form_Paint
End Sub
Private Sub Form_Unload(Cancel As Integer)
'Kill our API-timer
KillTimer Me.hwnd, 0
'Show all the typed keys
MsgBox sSave
End Sub

yufenfeila 2003-10-25

打赏
举报

也可以这样

一开始就计算当前时间与开始时间相差多少秒，然后用Sleep(x)让程序等待这些秒之后继续运行

请问如何用代码实现timer的功能，比如一秒之后raise一个event?

相关推荐