Question

我有一个Windows服务来从Exchange读取日历项目，并将它们存储在我的应用程序的数据库中以对抗每个用户。现在我想知道在Exchange上标记一个项目以便在存储后不能在下一个服务运行中检索的最佳方法是什么？

我尝试将扩展属性添加到日历项并设置其值，然后每次根据它的值进行搜索：

DateTime startDate = DateTime.Now;
DateTime endDate = startDate.AddDays(60);
const int NUM_APPTS = 60;    
// Set the start and end time and number of appointments to retrieve.
CalendarView cView = new CalendarView(startDate, endDate, NUM_APPTS);

Guid myPropertyId = new Guid("{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}");
ExtendedPropertyDefinition myExtendedProperty = new ExtendedPropertyDefinition(myPropertyId, "SyncFlag", MapiPropertyType.Boolean);

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

// Retrieve a collection of appointments by using the calendar view.
List<SearchFilter> searchFilterCollection = new List<SearchFilter>();
searchFilterCollection.Add(new SearchFilter.IsEqualTo(AppointmentSchema.Start, DateTime.Now));
searchFilterCollection.Add(new SearchFilter.IsEqualTo(AppointmentSchema.End, DateTime.Now.AddDays(60)));

searchFilterCollection.Add(new SearchFilter.IsNotEqualTo(myExtendedProperty, true)); //Do not fetch already marked calendar items

SearchFilter searchFilter = new SearchFilter.SearchFilterCollection(LogicalOperator.And, searchFilterCollection);

FindItemsResults<Item> appointments = service.FindItems(WellKnownFolderName.Calendar, searchFilter, cView);

使用此代码搜索日历项会引发此异常：

可能没有为CalendarView指定限制和排序顺序。

我不确定这是否也是最佳方式。有什么想法吗？

由于

Answer 1

一种方法是使用SyncFolderItems方法。它将返回自上次调用以来更改的项目。您所要做的就是保存同步＆＃34; cookie＆＃34;每次通话之间。

您还应该过滤掉自上次通话以来创建的约会项目。

下面的代码片段可以解决这个问题。

static private void GetChangedItems()
{
    // Path to cookie
    string syncStateFileName = @"c:\temp\ewssyncstate.txt";

    try
    {
        var service = GetServiceAP();
        bool moreChangesAvailable = false;

        do
        {
            string syncState = null;


            if (File.Exists(syncStateFileName))
            {
                // Read cookie
                syncState = File.ReadAllText(syncStateFileName);
            }

            ChangeCollection<ItemChange> icc = service.SyncFolderItems(new FolderId(WellKnownFolderName.Calendar), PropertySet.FirstClassProperties, null, 10, SyncFolderItemsScope.NormalItems, syncState);

            if (icc.Count == 0)
            {
                Console.WriteLine("There are no item changes to synchronize.");
            }
            else
            {
                syncState = icc.SyncState;

                // Save cookie
                File.WriteAllText(syncStateFileName, syncState);

                moreChangesAvailable = icc.MoreChangesAvailable;

                // Only get appointments that were created since last call
                var createdItems = icc
                    .Where(i => i.ChangeType == ChangeType.Create)
                    .Select(i => i.Item as Appointment)
                    ;

                if (createdItems.Any())
                {
                    service.LoadPropertiesForItems(createdItems, PropertySet.FirstClassProperties);

                    foreach (Appointment appointment in createdItems)
                    {
                        Console.WriteLine(appointment.Subject);
                    }
                }
            }
        }
        while (moreChangesAvailable);

    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

EWS托管Api - 仅检索一次日历项目

1 个答案: