Microsoft.Exchange.WebServices.Data.ServiceValidationException: FindItem 请求中不能使用 属性 RequiredAttendees

Question

我正在从 EWS 日历访问约会参加者。我试过了：

cView.PropertySet = new PropertySet(AppointmentSchema.Subject, AppointmentSchema.Start, AppointmentSchema.End);

但我的 appointments 列表条目每个都返回空 Required/Optional 参加者字段，即使测试约会已被多个用户接受。我的假设是 PropertySet 需要包含更多 ApplicationSchema 属性，如下所示：

cView.PropertySet = new PropertySet(AppointmentSchema.Subject,
                AppointmentSchema.Start,
                AppointmentSchema.End,
                AppointmentSchema.RequiredAttendees,
                AppointmentSchema.OptionalAttendees);

然而，这会在 calendar.FindAppointments(cView) 上引发以下 ServiceValidationException 错误：

Microsoft.Exchange.WebServices.Data.ServiceValidationException: The property RequiredAttendees can't be used in FindItem requests.

如何解决此问题以便 appointments 包括 required/optional 名与会者？

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);

service.Credentials = new WebCredentials(emailAddress, emailPassword);        

// Initialize values for the start and end times, and the number of appointments to retrieve.
DateTime startDate = DateTime.Now;
DateTime endDate = startDate.AddYears(1);
const int NUM_APPTS = 4;

// Initialize the calendar folder object with only the folder ID. 
CalendarFolder calendar = CalendarFolder.Bind(service, WellKnownFolderName.Calendar, new PropertySet());

// Set the start and end time and number of appointments to retrieve.
CalendarView cView = new CalendarView(startDate, endDate, NUM_APPTS);

// Limit the properties returned to the appointment's subject, start time, and end time.
cView.PropertySet = new PropertySet(AppointmentSchema.Subject,
     AppointmentSchema.Start,
     AppointmentSchema.End,
     AppointmentSchema.RequiredAttendees,
     AppointmentSchema.OptionalAttendees);

// Retrieve a collection of appointments by using the calendar view.
FindItemsResults<Appointment> appointments = calendar.FindAppointments(cView);

Answer 1

收件人是随 FindItems 操作不返回的正文的属性之一，您需要使用 GetItem 请求来获取这些属性，请参阅 https://msdn.microsoft.com/en-us/library/bb508824.aspx and https://blogs.msdn.microsoft.com/exchangedev/2010/03/16/loading-properties-for-multiple-items-with-one-call-to-exchange-web-services/