Office DocumentBeforeSave事件仅在绑定后几秒钟内起作用

Question

I'm working on a feature which is to create a backup when a open word saved each times. I'm using the blow code to hooking into word process and bind events to it, the word is opened by process.

officeApplication = (Application)Marshal.GetActiveObject("Word.Application").
officeApplication.DocumentBeforeSave += new ApplicationEvents4_DocumentBeforeSaveEventHandler(App_BeforeSaveDocument);

And in App_BeforeSaveDocument I did my work.

I get officeApplication right, and bind events were fine, when I click save in word, the events triggered perfectly. The problem is, a few seconds(may be 30s) after, the events will not fire anymore, no matter click save or save us or close document.

Is there any suggestions?

Answer 1

After a lot of researching, I still can't find the reason. And I decide to use a trick to approach it.

First, open a thread in the binding event:

static void App_BeforeSaveDocument(Microsoft.Office.Interop.Word.Document document, ref bool saveAsUI, ref bool cancel)
            {
                if (th != null)
                    th.Abort();
                th = new Thread(backupOnSave);
                th.IsBackground = true;
                th.Start(document);
            }

Then do an infinity loop in the thread:

internal static void backupOnSave(object obj)
        {
            try
            {
                Application app = obj as Application;
                if (app == null || app.ActiveDocument == null)
                {
                    return;
                }
                Microsoft.Office.Interop.Word.Document document = app.ActiveDocument;
                if (!tempData.ContainsKey(document.FullName))
                    return;
                var loopTicks = 2000;

                while (true)
                {
                    Thread.Sleep(loopTicks);
                    if (document.Saved)
                    {
                        if (!tempData.ContainsKey(document.FullName))
                            break;
                        var p = tempData[document.FullName];
                        var f = new FileInfo(p.FileFullName);

                        if (f.LastWriteTime != p.LastWriteTime)//changed, should create new backup
                        {
                            BackupFile(p, f);
                            p.LastWriteTime = f.LastWriteTime;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                log.write(ex);
            }
        }

And it works fine. Don't remember to abort the thread when the document closed or exception happen.