我想在Excel Addin上启用IMessageFilter
我必须写入excel。
我从here的例子中得到了例子:
消息过滤器是每个线程的,所以我们将此线程注册为 消息过滤器(不是创建加载项的主线程 - 因为那是Excel的主要线程
我的问题是,当计时器过去时,我的系统会写入excel,这会导致从ThreadPool线程调用写入方法,该线程会中断IMessageFilter
,因为excel无法访问RetryRejectedCall
IMessageFilter
部分1}},因为它存在于调用者线程而不是由计时器产生的执行线程。
所以,我的问题是:有没有办法可以强制计时器的Elapsed事件在初始化计时器的同一个线程上运行?
编辑:
我的问题是,如何在IMessageFilter
抛出拒绝/忙碌时抓住excel错误?
THX
答案 0 :(得分:7)
您可以使用Timer.SynchronizingObject
属性来封送在间隔过去时发出的事件处理程序调用。
来自MSDN:
当Elapsed事件由可视Windows窗体组件处理时, 例如按钮,通过系统线程访问组件 池可能会导致异常或者可能无法正常工作。避免这样做 通过将SynchronizingObject设置为Windows窗体组件, 这会导致调用处理Elapsed事件的方法 与创建组件的线程相同。
假设您正在使用WinFrom,并且您正在主窗体中创建计时器实例:
System.Timers.Timer t = new System.Timers.Timer();
t.SynchronizingObject = this;
t.Elapsed += t_Elapsed;
t.Start();
答案 1 :(得分:3)
完整的答案如下:
问题:将数据写入excel的类无法处理来自excel的“忙/拒绝”响应消息。
解决方案:按照here
所述实施IMessageFilter
界面
IMessageFilter
定义(来自链接):
namespace ExcelAddinMessageFilter
{
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct INTERFACEINFO
{
[MarshalAs(UnmanagedType.IUnknown)]
public object punk;
public Guid iid;
public ushort wMethod;
}
[ComImport, ComConversionLoss, InterfaceType((short)1),
Guid("00000016-0000-0000-C000-000000000046")]
public interface IMessageFilter
{
[PreserveSig, MethodImpl(MethodImplOptions.InternalCall,
MethodCodeType = MethodCodeType.Runtime)]
int HandleInComingCall([In] uint dwCallType, [In] IntPtr htaskCaller,
[In] uint dwTickCount,
[In, MarshalAs(UnmanagedType.LPArray)] INTERFACEINFO[]
lpInterfaceInfo);
[PreserveSig, MethodImpl(MethodImplOptions.InternalCall,
MethodCodeType = MethodCodeType.Runtime)]
int RetryRejectedCall([In] IntPtr htaskCallee, [In] uint dwTickCount,
[In] uint dwRejectType);
[PreserveSig, MethodImpl(MethodImplOptions.InternalCall,
MethodCodeType = MethodCodeType.Runtime)]
int MessagePending([In] IntPtr htaskCallee, [In] uint dwTickCount,
[In] uint dwPendingType);
}
}
IMessageFilter
我班级的实施部分(见链接):
#region IMessageFilter Members
int ExcelAddinMessageFilter.IMessageFilter.
HandleInComingCall(uint dwCallType, IntPtr htaskCaller, uint dwTickCount, ExcelAddinMessageFilter.INTERFACEINFO[] lpInterfaceInfo)
{
// We're the client, so we won't get HandleInComingCall calls.
return 1;
}
int ExcelAddinMessageFilter.IMessageFilter.
RetryRejectedCall(IntPtr htaskCallee, uint dwTickCount, uint dwRejectType)
{
// The client will get RetryRejectedCall calls when the main Excel
// thread is blocked. We can handle this by attempting to retry
// the operation. This will continue to fail so long as Excel is
// blocked.
// As an alternative to simply retrying, we could put up
// a dialog telling the user to close the other dialog (and the
// new one) in order to continue - or to tell us if they want to
// abandon this call
// Expected return values:
// -1: The call should be canceled. COM then returns RPC_E_CALL_REJECTED from the original method call.
// Value >= 0 and <100: The call is to be retried immediately.
// Value >= 100: COM will wait for this many milliseconds and then retry the call.
return 1;
}
int ExcelAddinMessageFilter.IMessageFilter.
MessagePending(IntPtr htaskCallee, uint dwTickCount, uint dwPendingType)
{
return 1;
}
#endregion
通过定义和实施IMessageFilter
接口,我按如下方式设置了STA Thread
和Timers.Timer
:
主题:
thread = new Thread(WriteToExcel);
thread.SetApartmentState(ApartmentState.STA);
计时器:
timer = new System.Timers.Timer();
timer.Interval = 2000;
timer.Elapsed += new ElapsedEventHandler(StartSTAThread_Handler);
其中StartSTAThread_Handler
定义为:
void StartSTAThread_Handler(object source, ElapsedEventArgs e)
{
thread.Start();
thread.Join();
thread = null;
}
此线程调用我用于写入Excel的方法,并使用上述IMessageFilter
接口处理被拒绝的消息。我要做的最后一件事就是完全符合excel OM参考资格,即;而不是:
Excel.Range rng = app.ActiveSheet.Range["range_name"];
rng.Copy(); // ERRROR: message filter's RetryRejectedCall is NOT called
我必须使用完全限定的引用:
app.ActiveSheet.Range["range_name"].Copy // OK: calls RetryRejectedCall when excel dialog etc is showing
虽然这似乎符合我的需要,但似乎与另一张海报here所描述的“双点规则”相矛盾......