尝试在Exchange安装程序中获取项目时出现C＃Outlook VSTO加载项错误

Question

我正在用C＃开发Office VSTO加载项，该加载项在Outlook中查找日历约会，并在其中读取/写入一些数据。

最近，其中一位客户的外接程序有问题，即他们无法读取/写入日历约会，并且抛出异常：

操作失败。

异常日志中没有太多信息，但是我怀疑它们在与Exchange同步方面存在问题。

我问客户，他们说，他们在Outlook中也有一个随机弹出窗口，有时在与Exchange同步时发生意外时会发生这种情况。 我告诉他们“修复” Outlook数据文件，但这并不能解决问题。

基本上基于Outlook EntryID或Subject查找Outlook项目（这些主题是唯一的，为了简单起见，我翻译了一下代码）

...main alghorythm...
    Outlook.AppointmentItem calAppointment = null;
    calAppointment = SearchforCalendarMatch(EntryID, Subject); //we try to find either by EntryID or by Subject
    if (calAppointment != null)
    {
        calAppointment.Start = StartDate;
        calAppointment.End = FinishDate;
        calAppointment.Body = Notes;
        calAppointment.Save(); //we're changing the found calendar appointment here
    }
...

public Outlook.AppointmentItem SearchforCalendarMatch(String EntryID, String Subject)
{
    Outlook.NameSpace ns = null;
    Outlook.MAPIFolder calendarFolder = null;
    Outlook.Items calendarFolderItems = null;
    Outlook.Items filteredcalendarFolderItems = null;
    Outlook.AppointmentItem calAppointment = null;

    Outlook.Application OutlookApp = new Outlook.Application();
    outlookversion = OutlookApp.Version;
    ns = OutlookApp.Session;

    //Try to find the calendar appointment by the EntryID
    dynamic OutlookItem = ns.GetItemFromID(t.Text28);
    if (OutlookItem != null)
    {
        if (OutlookItem is Outlook.AppointmentItem)
        {
            Outlook.AppointmentItem foundItem = (Outlook.AppointmentItem)OutlookItem;
            return foundItem;
        }
    }

    //If the EntryID was missing, we try to find the calendar appointment by the Subject. 
    //(original code is very long, and there are multiple things here, but let's just assume that 100% sure that the subject is unique, so it will find it)
    String SubjectMatch = "[Subject] = '" + Subject + "'";
    filteredcalendarFolderItems = calendarFolderItems.Restrict(SubjectMatch);
    for (int i = 1; i <= filteredcalendarFolderItems.Count; i++)
    {
        //appointment has to be one of these
        calAppointment = (Microsoft.Office.Interop.Outlook.AppointmentItem)filteredcalendarFolderItems[i];
        if (!calAppointment.IsConflict) //conflict check here, not sure if it helps at all
        {
            return calAppointment; //this is not the complete code, but this is the basic idea of it.
        }
    }
}

有什么想法可以使应用程序识别这些失败的Exchange同步并以不同的方式处理它们？

如果可能，我仍想在这些情况下进行同步...（在Outlook中更改“本地数据”，然后让Outlook处理所有内容）

Answer 1

您需要立即释放基础COM对象。 使用完后，使用System.Runtime.InteropServices.Marshal.ReleaseComObject释放Outlook对象。 如果您的加载项尝试枚举Microsoft Exchange Server上存储的集合中的256个以上Outlook项目，则这尤其重要。 如果不及时释放这些对象，则可以达到Exchange对任何一次打开的最大项目数施加的限制。 然后在Visual Basic中将变量设置为Nothing（在C＃中为null）以释放对该对象的引用。 在“ 系统发布对象”文章中了解有关此内容的更多信息。