protected override object InternalTryGetValue(PropertyBag.BasicPropertyStore propertyBag) { string itemClass = propertyBag.GetValue(InternalSchema.ItemClass) as string; ResponseType responseType; if (ObjectClass.IsMeetingPositiveResponse(itemClass)) { responseType = ResponseType.Accept; } else if (ObjectClass.IsMeetingTentativeResponse(itemClass)) { responseType = ResponseType.Tentative; } else { if (!ObjectClass.IsMeetingNegativeResponse(itemClass)) { return(propertyBag.GetValue(InternalSchema.MapiResponseType)); } responseType = ResponseType.Decline; } return(responseType); }