程序代码:
Option Explicit
'* 模块名称:clsTimer.cls 功能:在VB类模块中使用计时器
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare Function SetTimer Lib "user32" (ByVal hwnd As Long, ByVal nIDEvent As Long, ByVal uElapse As Long, ByVal lpTimerFunc As Long) As Long
Private Declare Function KillTimer Lib "user32" (ByVal hwnd As Long, ByVal nIDEvent As Long) As Long
Dim m_idTimer As Long
Dim m_Enabled As Boolean
Dim m_Interval As Long
Dim m_lTimerProc As Long
Private Sub Class_Initialize()
m_Interval = 0
m_lTimerProc = GetClassProcAddr(8)
End Sub
Private Sub Class_Terminate()
If m_idTimer <> 0 Then KillTimer 0, m_idTimer
End Sub
Public Property Get Interval() As Long
Interval = m_Interval
End Property
Public Property Let Interval(ByVal New_Value As Long)
If New_Value >= 0 Then m_Interval = New_Value
End Property
Public Property Get Enabled() As Boolean
Enabled = m_Enabled
End Property
Public Property Let Enabled(ByVal New_Value As Boolean)
m_Enabled = New_Value
If m_idTimer <> 0 Then KillTimer 0, m_idTimer
If New_Value And m_Interval > 0 Then
m_idTimer = SetTimer(0, 0, m_Interval, m_lTimerProc)
End If
End Property
Private Function GetClassProcAddr(ByVal Index As Long, Optional ParamCount As Long = 4, Optional HasReturnValue As Boolean) As Long
Static lReturn As Long, pReturn As Long
Static AsmCode(50) As Byte
Dim i As Long, pThis As Long, pVtbl As Long, pFunc As Long
pThis = ObjPtr(Me)
CopyMemory pVtbl, ByVal pThis, 4
CopyMemory pFunc, ByVal pVtbl + (6 + Index) * 4, 4
pReturn = VarPtr(lReturn)
For i = 0 To UBound(AsmCode)
AsmCode(i) = &H90
Next
AsmCode(0) = &H55
AsmCode(1) = &H8B: AsmCode(2) = &HEC
AsmCode(3) = &H53
AsmCode(4) = &H56
AsmCode(5) = &H57
If HasReturnValue Then
AsmCode(6) = &HB8
CopyMemory AsmCode(7), pReturn, 4
AsmCode(11) = &H50
End If
For i = 0 To ParamCount - 1
AsmCode(12 + i * 3) = &HFF
AsmCode(13 + i * 3) = &H75
AsmCode(14 + i * 3) = (ParamCount - i) * 4 + 4
Next
i = i * 3 + 12
AsmCode(i) = &HB9
CopyMemory AsmCode(i + 1), pThis, 4
AsmCode(i + 5) = &H51
AsmCode(i + 6) = &HE8
CopyMemory AsmCode(i + 7), pFunc - VarPtr(AsmCode(i + 6)) - 5, 4
If HasReturnValue Then
AsmCode(i + 11) = &HB8
CopyMemory AsmCode(i + 12), pReturn, 4
AsmCode(i + 16) = &H8B
AsmCode(i + 17) = &H0
End If
AsmCode(i + 18) = &H5F
AsmCode(i + 19) = &H5E
AsmCode(i + 20) = &H5B
AsmCode(i + 21) = &H8B: AsmCode(i + 22) = &HE5
AsmCode(i + 23) = &H5D
AsmCode(i + 24) = &HC3
GetClassProcAddr = VarPtr(AsmCode(0))
End Function
Private Sub TimerProc(ByVal hwnd As Long, ByVal uMsg As Long, ByVal idEvent As Long, ByVal dwTime As Long)
Debug.Print "类模板中的计时器:", uMsg, idEvent, dwTime
End Sub
二、测试代码如下:
Dim m_tm As clsTimer
Private Sub Form_Load()
Set m_tm = New clsTimer
End Sub
Private Sub Form_Unload(Cancel As Integer)
Set m_tm = Nothing
End Sub
Private Sub Command1_Click()
m_tm.Interval = 1000
m_tm.Enabled = True
End Sub
Private Sub Command2_Click()
m_tm.Enabled = False
End Sub
这是从网上找的一段代码,功能是一个计时器,是在类模块中实现子类的示例。
但这段代码的原理看不懂,不懂原理就很难修改,更不能举一反三的灵活运行
按照我的理解:“GetClassProcAddr”的返回值是“TimerProc”的内存地址,而且调用GetClassProcAddr时的参数只能是8,因为TimerProc的位置在第8,其余的就看不懂了。
所以我想,有没有一个第三方软件(或工具)能看到“TimerProc”的内存地址,这样可以和我在VB中调试时的结果相对照,以此来保证调试的正确性。