EWS - ExtendedProperty Security

See more:

C#3.0

C#

EWS

Exchange-Server

Hi all,
In my experience with EWS, why is it necessary to add additional security right on Exchange when querying ExtendedProperty data. When I make use of the following code:

public ExtendedPropertyType[] GetExtendedProperties(ItemIdType itemid)
{
    PathToExtendedFieldType pathClassification = new PathToExtendedFieldType();
    pathClassification.DistinguishedPropertySetId = 
       DistinguishedPropertySetType.PublicStrings;
    pathClassification.DistinguishedPropertySetIdSpecified = true;
    pathClassification.PropertyName = "Classification";
    pathClassification.PropertyType = MapiPropertyTypeType.String;


    GetItemType getExPropertiesRequest = new GetItemType();
    ItemIdType iiItemId = new ItemIdType();
    iiItemId = itemid;

    ItemResponseShapeType getResponseShape = new ItemResponseShapeType();
    getResponseShape.BaseShape = DefaultShapeNamesType.AllProperties;
    getResponseShape.IncludeMimeContent = true;
    getExPropertiesRequest.ItemShape = getResponseShape;

    getExPropertiesRequest.ItemShape.AdditionalProperties = 
                                     new BasePathToElementType[1];
    getExPropertiesRequest.ItemShape.AdditionalProperties[0] = pathClassification;


    getExPropertiesRequest.ItemIds = new ItemIdType[1];
    getExPropertiesRequest.ItemIds[0] = iiItemId;
    getExPropertiesRequest.ItemShape.BaseShape = DefaultShapeNamesType.AllProperties;

    GetItemResponseType giResponse = _esb.GetItem(getExPropertiesRequest);
    if (giResponse.ResponseMessages.Items[0].ResponseClass == ResponseClassType.Error)
    {
        throw new Exception("Error: " +
        giResponse.ResponseMessages.Items[0].MessageText);
    }
    else
    {
        ItemInfoResponseMessageType rmResponseMessage = 
             giResponse.ResponseMessages.Items[0] as ItemInfoResponseMessageType;

        if (rmResponseMessage.Items.Items[0].ExtendedProperty != null)
        {
            MessageType message = rmResponseMessage.Items.Items[0] as MessageType;
            return (message.ExtendedProperty);
        }
        else
        {
            return null;
        }
    }
}

I require full access permissions, otherwise I cannot query extended property data.
Why is this? Could someone please explain?

I even tried developing against EWS API - here is the code:

class Program
    {
        static void Main(string[] args)
        {
            ServicePointManager.ServerCertificateValidationCallback =
                delegate(Object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
                {
                    return true;
                };

            try
            {
                // Connect to Exchange Web Services as user1 at contoso.com.
                ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010);
                service.Credentials = new NetworkCredential("user.name", "password123", Environment.UserDomainName);
                service.Url = new Uri("https://mailserver/EWS/Exchange.asmx");

                ItemView iv = new ItemView(30);
                FolderId Folderid = new FolderId(WellKnownFolderName.Calendar, "boardroomd123@qmuzik.com");
                FindItemsResults<Item> fiResults = service.FindItems(Folderid, iv);

                ExtendedPropertyDefinition rmsActivityProp = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.PublicStrings, "OnQGuid", MapiPropertyType.String);
                ExtendedPropertyDefinition[] userFields = new ExtendedPropertyDefinition[] { rmsActivityProp };
                iv.PropertySet = new PropertySet(BasePropertySet.FirstClassProperties, userFields);
                FindItemsResults<Item> findResults = service.FindItems(Folderid, iv);

                Appointment appt = null;

                foreach (Item item in findResults.Items)
                {
                    if (item != null && item is Appointment)
                    {
                        appt = item as Appointment;

                        Console.ForegroundColor = ConsoleColor.Magenta;
                        Console.WriteLine("> Appointment Subject: {0}", appt.Subject);
                        Console.WriteLine("> Start Date: {0}", appt.Start);
                        Console.WriteLine("> End Date: {0}", appt.End);
                        Console.WriteLine("> Extended Properties Count: {0}", appt.ExtendedProperties.Count);

                        if (item.ExtendedProperties.Count > 0)
                        {
                            // Display the extended name and value of the extended property.
                            foreach (ExtendedProperty extendedProperty in item.ExtendedProperties)
                            {
                                Console.ForegroundColor = ConsoleColor.Cyan;
                                Console.WriteLine("# Extended Property Name: {0}", extendedProperty.PropertyDefinition.Name);
                                Console.WriteLine("# Extended Property Value: {0}", extendedProperty.Value);
                            }
                        }
                        else
                        {
                            Console.ForegroundColor = ConsoleColor.Red;
                            Console.WriteLine("# NO Extended Property Data Found");
                        }

                        Console.ForegroundColor = ConsoleColor.Yellow;
                        Console.WriteLine("-----------------------------------------------------------");
                    }                    
                }

                Console.ForegroundColor = ConsoleColor.White;
                Console.WriteLine("Done....Processed: {0} Items", iv.PageSize);
                Console.ReadLine();
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error: " + ex.Message);
                Console.ReadLine();
            }
        }
    }

And it still requires the additional security to query the extended properties? Here is the output when an user account has been configured without any permissions:
Error: The specified folder could not be found in the store.

Could someone please explain??

Many thanks again!
Kind regards,