运行 COM（自制）计时器时，我在 Excel 中遇到错误。基本上Excel实例化定时器，初始化它并启动它。然后计时器每 X 毫秒计时一次，引发 Excel 捕获的事件（非常标准的东西）。我没有将 Excel 本身用作计时器，因为它的滴答速度不会比每秒快（这对我来说太长了）
我的问题是，如果我在计时器引发事件时单击并按住电子表格，Excel 会严重崩溃。不幸的是，用户需要（有时）在电子表格中单击并在计时器运行时对其进行修改。
我在某个地方看到我可以在我的计时器中使用 IMessageFilter 接口。这应该确保如果在事件触发时 Excel 很忙，则计时器可以看到这一点并采取相应的行动。但是我无法正确实施它。
如果有人可以帮助我，那就太好了。
这是我正在使用的源代码：
在 Excel 中，我有一个带有 WithEvents ExcelTimer.ExcelTimer 对象的单例，这是我的单例的代码：
Option Explicit
Private Const m_sMODULE_NAME = "cTimerManager"
Public WithEvents oCsharpTimer As ExcelTimer.ExcelTimer
Private Sub Class_Initialize()
Set oCsharpTimer = New ExcelTimer.ExcelTimer
'The following two lines are called dynamically from somewhere else
'normally but for simplicity of my post I have put them here
oCsharpTimer.Initialize 500
oCsharpTimer.StartTimer
End Sub
Private Sub oCsharpTimer_TimeTickEvt(ByVal o As Variant, ByVal Time As String)
Const sPROCEDURE_NAME = "oCsharpTimer_TimeTickEvt"
On Error GoTo ErrorHandler
'"Send" confirmation with time to the COM object.
oCsharpTimer.TimeReceived Time
'Do whatever I wanna do when the event is trigger
CleanUp:
Exit Sub
ErrorHandler:
'My Error handling structure
If ProcessError(m_sMODULE_NAME, sPROCEDURE_NAME, Err) Then
Stop
Resume
Else
Resume Next
End If
End Sub
这是我的 COM 对象的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace ExcelTimer
{
public delegate void EventTimeRaiser(object o, string Time);
//COM Interface
public interface ICOMExcelTimer
{
[DispId(1)]
void StartTimer();
[DispId(2)]
void StopTimer();
[DispId(3)]
void Initialize(int TimeInMilliseconds);
[DispId(4)]
void TimeReceived(string ReceivedTime);
}
//Event interface
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface ICOMExcelTimerEvent
{
[DispId(1000)]
void TimeTickEvt(object o, string Time);
}
[ClassInterface(ClassInterfaceType.None),
ComSourceInterfaces(typeof(ICOMExcelTimerEvent)),
ComVisible(true)]
public class ExcelTimer : ICOMExcelTimer, IMessageFilter
{
private event EventTimeRaiser TimeTickEvt;
private bool _started;
private bool _initialised;
private int _timeInMilliseconds;
private string _lastTimeReceived;
private Control _control;
private Thread _timerThread;
private IAsyncResult _AsynchronousResult;
[ComVisible(true)]
public void Initialize(int TimeInMilliSeconds)
{
//To be called by Excel to set which timer parameters it wants
_timeInMilliseconds = TimeInMilliSeconds;
_initialised = true;
//Make sure we clear the last confirmation received
//since we are re-initialising the object
_lastTimeReceived = "";
}
[ComVisible(true)]
public void TimeReceived(string ReceivedTime)
{
//Store the last time received. Excel calls this function
_lastTimeReceived = ReceivedTime;
}
public ExcelTimer()
{
_lastTimeReceived = "";
}
[ComVisible(true)]
//Start the Timer
public void StartTimer()
{
//If the timer has not been initialised just yet
if (!_initialised)
{
//Sends back an error message to Excel
TimeTickEvt(this, "Error: Timer Not Initialised");
return;
}
try
{
//Start the timer
_timerThread = new Thread(new ThreadStart(TimeTicking));
//Start the Thread
_started = true;
_timerThread.Start();
}
catch (Exception ex)
{
System.IO.File.AppendAllText(@"C:\ErrorLog.txt", ex.Message + " - StartTimer - " + DateTime.Now.ToString("hh:mm:ss.f") + "\n");
}
}
[ComVisible(true)]
//Stop the timer
public void StopTimer()
{
//Stop the Thread
_timerThread.Abort();
//Change the status
_started = false;
}
private void TimeTicking()
{
string SentTime;
//As long as the timer is running
while (_started)
{
try
{
//Pause the timer for the right number of milliseconds
Thread.Sleep(_timeInMilliseconds);
SentTime = DateTime.Now.ToString("hh:mm:ss.ffff");
//########### The CODE Errors Here when Excel is busy! ###########
//Raise an event for Excel to grab with the time that the thread finished the sleep at.
OnTimeTick(SentTime);
//_lastTimeReceived is used so that if the link between Excel and the Thread is broken the thread stops after sometimes
//if no confirmation was received from Excel.
//If no last time was received just yet, we setup the last time received to the sent time
if (_lastTimeReceived.Equals(""))
{
_lastTimeReceived = SentTime;
}
//If the last time received is older than 10 x TimeInMilliseconds (in Seconds) we stop the timer.
else if (Convert.ToDateTime(_lastTimeReceived).AddSeconds(_timeInMilliseconds * 10 / 1000) < Convert.ToDateTime(SentTime))
{
OnTimeTick("Timer timed out. No Confirmation for more than " + _timeInMilliseconds * 10 / 1000 + " second(s).");
//Stop the timer because the thread has not received a last time recently
_started = false;
}
}
catch (Exception ex)
{
System.IO.File.AppendAllText(@"C:\ErrorLog.txt", ex.Message + " - TimeTicking - " + DateTime.Now.ToString("hh:mm:ss.f") + "\n");
}
}
}
protected virtual void OnTimeTick(string Time)
{
try
{
if (Time != null)
{
//Raise the event
TimeTickEvt(this, Time);
}
}
catch (Exception ex)
{
System.IO.File.AppendAllText(@"C:\ErrorLog.txt", ex.Message + " - OnTimeTick - " + DateTime.Now.ToString("hh:mm:ss.f") + "\n");
}
}
}
}