BExIS.Dcm.CreateDatasetWizard.UsageHelper.GetSimpleUsageById C# (CSharp) Метод

        public static BaseUsage GetSimpleUsageById(BaseUsage parent, long Id)
        {
            BaseUsage usage = new BaseUsage();

            if (parent is MetadataPackageUsage)
            {
                MetadataPackageManager mpm = new MetadataPackageManager();

                var q = from p in mpm.MetadataPackageRepo.Get()
                        from u in p.MetadataAttributeUsages
                        where p.Id.Equals(parent.Id) && u.Id == Id && u.MetadataAttribute.Self is MetadataSimpleAttribute
                        select u;

                if (q != null && q.ToList().Count > 0)
                {
                    return q.FirstOrDefault();
                }
                else return null;
            }

            else
            if (parent is MetadataNestedAttributeUsage)
            {
                MetadataAttributeManager mam = new MetadataAttributeManager();

                MetadataNestedAttributeUsage pUsage = (MetadataNestedAttributeUsage)parent;

                MetadataCompoundAttribute mca = mam.MetadataCompoundAttributeRepo.Get(pUsage.Member.Self.Id);

                var x = from nestedUsage in mca.MetadataNestedAttributeUsages
                        where nestedUsage.Id == Id && nestedUsage.Member.Self is MetadataSimpleAttribute
                        select nestedUsage;

                //var x = from c in mam.MetadataCompoundAttributeRepo.Get()
                //        from u in c.Self.MetadataNestedAttributeUsages
                //        where u.Id.Equals(parent.Id) && u.Member.Self.Id == Id && u.Member.Self is MetadataSimpleAttribute
                //        select u;

                return x.FirstOrDefault();
            }
            else if (parent is MetadataAttributeUsage)
            {
                MetadataAttributeUsage mau = (MetadataAttributeUsage)parent;
                if (mau.MetadataAttribute.Self is MetadataCompoundAttribute)
                {
                    MetadataCompoundAttribute mca = (MetadataCompoundAttribute)mau.MetadataAttribute.Self;
                    return mca.MetadataNestedAttributeUsages.Where(m => m.Id.Equals(Id)).FirstOrDefault();
                }

            }

            return null;
        }