Exchange Web服务:为什么ItemId不是常量？[继续]

Question

正如其他一些人之前讨论过这个问题(例如,Exchange Web服务:为什么ItemId不是常数？),我想谈谈解决方案,我已经做了人们通过将Guid标记为扩展属性而建议的内容,对我而言解决方案有点好(虽然我不知道如何使其与出现的一起工作)但只要应用程序正常工作,一旦应用程序重新启动项目的扩展属性消失,所以我现在的问题是" 如何在EWS项目上标记扩展属性并使其不断存在？"这是更新日历项目(约会)的代码

public void SetGuidForAppointement(Appointment appointment)
{         
appointment.SetExtendedProperty((ExtendedPropertyDefinition)_appointementIdPropertyDefinition, Guid.NewGuid().ToString());
appointment.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendToNone);
}

这些是上面需要的属性定义.

_appointementIdPropertyDefinition = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.Appointment, "AppointmentID", MapiPropertyType.String);
            _propertyDefinitionBases = new PropertyDefinitionBase[] { _appointementIdPropertyDefinition, ItemSchema.ParentFolderId, AppointmentSchema.Start, AppointmentSchema.End, 
AppointmentSchema.LegacyFreeBusyStatus, AppointmentSchema.Organizer };
            PropertySet = new PropertySet(BasePropertySet.FirstClassProperties, _propertyDefinitionBases);

因此,如果有人在此之前完成此操作,他/她可以向我提供一个示例,即使应用程序退出,也会将扩展属性标记在项目上.谢谢

Answer 1

经过一段时间的尝试和搜索,我找到了解决问题的方法.

private static readonly PropertyDefinitionBase AppointementIdPropertyDefinition = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.PublicStrings, "AppointmentID", MapiPropertyType.String);
public static PropertySet PropertySet = new PropertySet(BasePropertySet.FirstClassProperties, AppointementIdPropertyDefinition);


//Setting the property for the appointment 
 public static void SetGuidForAppointement(Appointment appointment)
{
    try
    {
        appointment.SetExtendedProperty((ExtendedPropertyDefinition)AppointementIdPropertyDefinition, Guid.NewGuid().ToString());
        appointment.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendToNone);
    }
    catch (Exception ex)
    {
        // logging the exception
    }
}

//Getting the property for the appointment
 public static string GetGuidForAppointement(Appointment appointment)
{
    var result = "";
    try
    {
        appointment.Load(PropertySet);
        foreach (var extendedProperty in appointment.ExtendedProperties)
        {
            if (extendedProperty.PropertyDefinition.Name == "AppointmentID")
            {
                result = extendedProperty.Value.ToString();
            }
        }
    }
    catch (Exception ex)
    {
     // logging the exception
    }
    return result;
}