文件更改事件被调用两次

Question

文件更改事件被调用两次

6

我使用 IVsFileChangeEvents 和 IVsFileChangeEx 的组合来监测自定义编辑器扩展中的文件是否在IDE外被修改。然而，由于某种未知的原因，我会收到两次通知，导致需要两次要求用户重新加载。 FilesChanged的实现如下所示：

    public int FilesChanged(uint cChanges, string[] rgpszFile, uint[] rggrfChange) {

        foreach (var file in rgpszFile)
        {
            if (file.ToLowerInvariant() == documentPath.ToLowerInvariant()) {

                System.Diagnostics.Debug.WriteLine("File changed - asking for reload");

                if (MessageBox.Show("The file {0} was changed outside the editor. Do you want to reload it?".FillWith(file), 
                    "MyEditor", 
                    MessageBoxButton.YesNo, 
                    MessageBoxImage.Question) == MessageBoxResult.Yes) {

                    fileChangeEx.IgnoreFile(fileCookie, null, 1);

                    // Unloading document
                    DoCloseDocument();

                    // Loading document
                    DoLoadDocument(file);

                    fileChangeEx.SyncFile(documentPath);
                    fileChangeEx.IgnoreFile(fileCookie, null, 0);
                }
            }
        }
        return VSConstants.S_OK;
    }

我使用Notepad++保存相同的文件来测试这段代码。

这是SysInternals' ProcMon的日志:

09:05:21,2272369    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:21,2273658    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:21,2275512    notepad++.exe   256 QueryDirectory  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Filter: settings.definition, 1: settings.definition
09:05:28,7692878    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:28,7694244    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:28,7696066    notepad++.exe   256 QueryDirectory  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Filter: settings.definition, 1: settings.definition
09:05:44,0463636    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:46,4087520    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:46,4088700    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:46,4089646    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 08:50:27, ChangeTime: 2014-05-23 08:50:27, AllocationSize: 4 096, EndOfFile: 1 740, FileAttributes: A
09:05:46,4090631    notepad++.exe   256 CreateFile  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Desired Access: Generic Write, Read Attributes, Dis, Options: Synchronous IO Non-Alert, Non-Directory File, Attributes: N, ShareMode: Read, Write, AllocationSize: 0, OpenResult: Overwritten
09:05:46,4100654    notepad++.exe   256 WriteFile   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Offset: 0, Length: 1 742, Priority: Normal
09:05:46,4101850    notepad++.exe   256 CloseFile   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS 
09:05:46,4102751    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4103088    MsMpEng.exe 956 CreateFileMapping   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   FILE LOCKED WITH WRITERS    SyncType: SyncTypeCreateSection, PageProtection: 
09:05:46,4103322    MsMpEng.exe 956 QueryStandardInformationFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS AllocationSize: 4 096, EndOfFile: 1 742, NumberOfLinks: 1, DeletePending: False, Directory: False
09:05:46,4144664    notepad++.exe   256 QueryDirectory  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Filter: settings.definition, 1: settings.definition
09:05:46,4160238    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4172362    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4173472    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4175063    notepad++.exe   256 QueryDirectory  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Filter: settings.definition, 1: settings.definition
09:05:46,4178437    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4185672    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:05:46,4186404    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:06:06,8788282    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:06:06,8789555    notepad++.exe   256 QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:06:06,8791373    notepad++.exe   256 QueryDirectory  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Filter: settings.definition, 1: settings.definition
09:06:50,6465883    devenv.exe  6884    CreateFile  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Desired Access: Generic Read, Dis, Options: Synchronous IO Non-Alert, Non-Directory File, Open No Recall, Attributes: n/a, ShareMode: Read, AllocationSize: n/a, OpenResult: Opened
09:06:50,6466482    devenv.exe  6884    QueryStandardInformationFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS AllocationSize: 4 096, EndOfFile: 1 742, NumberOfLinks: 1, DeletePending: False, Directory: False
09:06:50,6466665    devenv.exe  6884    ReadFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Offset: 0, Length: 1 742, Priority: Normal
09:06:50,6467374    devenv.exe  6884    ReadFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   END OF FILE Offset: 1 742, Length: 4 096
09:06:50,6469314    devenv.exe  6884    CloseFile   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS 
09:06:50,6477175    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:06:50,6963339    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:07:02,3340501    devenv.exe  6884    CreateFile  D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Desired Access: Generic Read, Dis, Options: Synchronous IO Non-Alert, Non-Directory File, Open No Recall, Attributes: n/a, ShareMode: Read, AllocationSize: n/a, OpenResult: Opened
09:07:02,3341050    devenv.exe  6884    QueryStandardInformationFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS AllocationSize: 4 096, EndOfFile: 1 742, NumberOfLinks: 1, DeletePending: False, Directory: False
09:07:02,3341200    devenv.exe  6884    ReadFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS Offset: 0, Length: 1 742, Priority: Normal
09:07:02,3341887    devenv.exe  6884    ReadFile    D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   END OF FILE Offset: 1 742, Length: 4 096
09:07:02,3343792    devenv.exe  6884    CloseFile   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS 
09:07:02,3351733    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A
09:07:02,3626280    devenv.exe  6884    QueryOpen   D:\VS Projects\Temporary\WindowsFormsApplication1\WindowsFormsApplication1\NewFolder1\settings.definition   SUCCESS CreationTime: 2014-05-21 13:08:34, LastAccessTime: 2014-05-21 13:08:34, LastWriteTime: 2014-05-23 09:05:46, ChangeTime: 2014-05-23 09:05:46, AllocationSize: 4 096, EndOfFile: 1 742, FileAttributes: A

看起来MessageBox.Show调用是第二个通知的主要原因。

调用堆栈如下所示：

MyAssembly.dll!MyClass.FilesChanged(uint cChanges = 1, string[] rgpszFile = {string[1]}, uint[] rggrfChange = {uint[1]}) Line 284   C#
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.FileChangeSubscription.Notify.AnonymousMethod__0() Unknown
Microsoft.VisualStudio.Shell.12.0.dll!Microsoft.VisualStudio.ErrorHandler.CallWithCOMConvention(System.Func<int> method, bool reportError = false, bool setShellErrorInfo = true)   Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.FileChangeSubscription.Notify(Microsoft.VisualStudio.Shell.Interop._VSFILECHANGEFLAGS changes) Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.FileChangeSubscription.Notify(System.IO.WatcherChangeTypes changeTypes, Microsoft.VisualStudio.Services.FileProperties props)  Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.FileWatcher.Notify(Microsoft.VisualStudio.Services.ChangeStreamDigest digest)  Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.DirectoryWatcher.ProcessFileChanges(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,Microsoft.VisualStudio.Services.ChangeStreamDigest>> digests, int depth) Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.DirectoryWatcher.ProcessChanges(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,Microsoft.VisualStudio.Services.ChangeStreamDigest>> digests = Count = 1, int depth = 3) Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.DirectoryWatcher.ProcessChanges(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,Microsoft.VisualStudio.Services.ChangeStreamDigest>> digests = Count = 1, int depth = 2) Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.DirectoryWatcher.ProcessChanges(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,Microsoft.VisualStudio.Services.ChangeStreamDigest>> digests = {Microsoft.Internal.VisualStudio.PlatformUI.HybridDictionary<string,Microsoft.VisualStudio.Services.ChangeStreamDigest>}, int depth = 1)  Unknown
Microsoft.VisualStudio.Shell.UI.Internal.dll!Microsoft.VisualStudio.Services.DirectoryWatcher.OnChangedAsync()  Unknown
WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs)  Unknown
WindowsBase.dll!MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(object source = {System.Windows.Threading.Dispatcher}, System.Delegate method, object args, int numArgs, System.Delegate catchHandler = null)  Unknown
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.InvokeImpl()   Unknown
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(object state)  Unknown
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.Invoke()   Unknown
WindowsBase.dll!System.Windows.Threading.Dispatcher.ProcessQueue()  Unknown
WindowsBase.dll!System.Windows.Threading.Dispatcher.WndProcHook(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled)  Unknown
WindowsBase.dll!MS.Win32.HwndWrapper.WndProc(System.IntPtr hwnd = 264738, int msg = 49778, System.IntPtr wParam = 0, System.IntPtr lParam = 0, ref bool handled = false)    Unknown
WindowsBase.dll!MS.Win32.HwndSubclass.DispatcherCallbackOperation(object o) Unknown
WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs)  Unknown
WindowsBase.dll!MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(object source = {System.Windows.Threading.Dispatcher}, System.Delegate method, object args, int numArgs, System.Delegate catchHandler = null)  Unknown
WindowsBase.dll!System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, object args, int numArgs)   Unknown
WindowsBase.dll!MS.Win32.HwndSubclass.SubclassWndProc(System.IntPtr hwnd = 264738, int msg = 49778, System.IntPtr wParam = 0, System.IntPtr lParam = 0) Unknown
[Native to Managed Transition]  
[Managed to Native Transition]  
PresentationFramework.dll!System.Windows.MessageBox.ShowCore(System.IntPtr owner, string messageBoxText, string caption, System.Windows.MessageBoxButton button, System.Windows.MessageBoxImage icon, System.Windows.MessageBoxResult defaultResult, System.Windows.MessageBoxOptions options)  Unknown
PresentationFramework.dll!System.Windows.MessageBox.Show(string messageBoxText, string caption, System.Windows.MessageBoxButton button, System.Windows.MessageBoxImage icon)    Unknown
MyAssembly.dll!MyClass.FilesChanged(uint cChanges = 1, string[] rgpszFile = {string[1]}, uint[] rggrfChange = {uint[1]}) Line 290   C#

我该怎么做才能只接收到一次事件？

- Spook

这可能是由于再次关闭和打开文件引起的。如果您重新运行实验但注释掉DoCloseDocument和DoLoadDocument方法，会发生什么？ - Philip Pittle

看一下调用堆栈。在调用 MessageBox 后，第二次调用 FilesChanged 立即发生，因此 Close/Load 方法尚未被执行。 - Spook

3个回答

1

我曾在Win32级别的文件更改事件中遇到类似的问题。有许多方法可以减少问题（如断开事件连接）。实际上，在处理事件时，您不知道文件可能被“更改”多少次。对于基于消息的事件，只需要调用处理消息的任何东西即可重新进入，对于多线程事件，无论您做什么都可能发生。因此，当接收到通知时，您应该非常小心。理想情况下，您的事件处理程序应该以一种方式编写，以便在仍在处理先前事件时可以处理再次调用。根据对话框和后续处理的内容，您可以只跟踪它是否打开和/或正在处理并忽略任何并发事件，或者您可能需要通知对话框或处理代码发生了另一种更改。断开和重新连接通知适用于基于消息的事件，但如果存在任何线程，则不适用。

- James

0

通过显示一个消息框，你实际上创建了一个新的消息循环，从而允许潜在的重入。这与从VS的角度来看FilesChanged事件尚未完成运行（你还没有从函数中返回）可能会导致奇怪的行为。

在处理程序中立即返回。使用ThreadHelper.Generic.BeginInvoke排队消息框和文档重新加载。

- Julien Lebosquain

不幸的是，这并没有改变任何事情。现在，以messagebox开头的整个块（if语句的内容）都在BeginInvoke内部，但尽管如此，messagebox仍然显示两次。 - Spook

@Spook 噢，也许有两个不同标志的调用：一个是VSFILECHG_Time，另一个是VSFILECHG_Size？ - Julien Lebosquain

我猜这不是问题，因为我只要求VS监视时间。而且，第二个调用明确发生在MessageBox调用之后，所以你提出的原因似乎是合理的。最后，在注释掉Messagebox之后，方法只被调用一次。问题是，我怎样才能以正确的方式显示消息框 :) - Spook

可能还有其他需要排队的调用...你可以尝试使用计时器延迟消息框，看看是否有效，但这并不是一个合适的解决方案。 - Julien Lebosquain

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Alexander Pacha · Accepted Answer

我通过在方法中分离通知并在最后重新附加它们来使其正常工作。

大致如下（请注意，我省略了有关serviceProvider、fileChangeCookie、filesChanged数组等的一些详细信息）

int IVsFileChangeEvents.FilesChanged(uint numberOfFilesChanged, string[] filesChanged, uint[] flags) 
{
    IVsFileChangeEx fileChangeService = yourServiceProvider.GetService(typeof(SVsFileChangeEx));
    // Detach from notifications
    fileChangeService.UnadviseFileChange(GetCookieFromFile(filesChanged[0]));
    // Do your stuff with the file
    ...
    // Re-attach to notifications
    fileChangeService.AdviseFileChange(filesChanged[0], (uint)(_VSFILECHANGEFLAGS.VSFILECHG_Time | _VSFILECHANGEFLAGS.VSFILECHG_Del), this, out fileChangeCookie);
}