c# - OrganizationServiceContext から「null 値」を取得する

Question

OrganizationServiceContext.CreateQueryC# とメソッドを使用して、CRM 2011 で空の列 "null 値" を取得する際に問題が発生しています。私のコードは以下です。問題はSubType. null の場合、「オブジェクトがオブジェクトのインスタンスに設定されていません」というエラーが表示されます。誰でも助けてもらえますか？

    public List<Opportunities> GetOpportunitiesList()
    {
        using (_orgService = new OrganizationService(connection))
        {
            OrganizationServiceContext context = new OrganizationServiceContext(_orgService);
            // Create Linq Query.
            DateTime getdate = DateTime.Now.AddDays(-3);
            var query = (from r in context.CreateQuery<Opportunity>()
                         join c in context.CreateQuery<Contact>() on r.ContactId.Id equals c.ContactId
                             into rc
                         from z in rc.DefaultIfEmpty()
                         where r.CreatedOn > getdate && r.new_type.Value != null
                         orderby r.ContactId
                         select new Opportunities
                         {
                             opporunity = r.new_OpportunityNumber,
                             //region =GetAccountRegionsbyId(a.new_region.Value),  
                             accountid = r.CustomerId.Id,
                             topic = r.Name,
                             status = r.StateCode.Value.ToString(),
                             pcustomer = r.CustomerId.Name,
                             estReve = (decimal)r.EstimatedValue.Value,
                             owner = r.OwnerId.Name,
                             salesstagecode = r.SalesStageCode.Value,
                             pipelinePhase = r.StepName,
                             opptype = getAllOptionSetValues(r.LogicalName, "new_sf_recordtype", r.new_sf_recordtype.Value),
                             subtype = getAllOptionSetValues(r.LogicalName, "new_type", r.new_type.Value == null ? default(int) : r.new_type.Value),
                             estclosedate = r.EstimatedCloseDate.Value,
                             actualRev = (Microsoft.Xrm.Sdk.Money)r.ActualValue,
                             probability = r.CloseProbability.Value,
                             weighedRev = (decimal)r.new_WeightedValue.Value,
                             Email = z.EMailAddress1,
                             CreatedOn = r.CreatedOn.Value,
                             modifiedBy = r.ModifiedBy.Name,

                             modifiedOn = r.ModifiedOn.Value
                         }).ToList();
            foreach (Opportunities o in query)
            {
                o.region = (from d in context.CreateQuery<Account>() where d.AccountId == o.accountid select getAllOptionSetValues(d.LogicalName, "new_region", d.new_region.Value)).FirstOrDefault();

            }
            return query;
        }
    }