c# - Entity Framework Navigation Properties are not listed while creating a converter -

i have following working entity frameowrk code creating dto entity framework result. created invoicedto object has list<servicechargedto> property inside it. done referring mapping linq query results dto class

public class invoicedto {     public int invoiceid { get; set; }     public list<servicechargedto> servicechargelineitems { get; set; }     public decimal invoicetotal { get; set; } }   public invoicedto getinvoicebyid(int invoiceidparam) {     invoicedto invoice=null;     using (var db = new portalentities())     {         var invoices = in db.invoices                        a.invoiceid == invoiceidparam                        select new invoicedto                        {                            invoiceid = a.invoiceid,                            invoicetotal = a.invoiceamount,                            servicechargelineitems =                                 (from b in db.invoiceservicexrefs                                  a.invoiceid == b.invoiceid                                  select new servicechargedto                                 {                                     servicechargeid = b.servicechargeid,                                     quantity = b.servicecharge.qty,                                     unitprice=b.servicecharge.unitprice,                                     amount=b.servicecharge.amount                                 }                                 ).tolist()                        };          invoice = invoices.firstordefault();     }      return invoice; } 

here data related tables retrieved.

invoiceservicexrefs.servicecharge.qty 

i need change approach , make convert method.

public invoicedto getinvoicebyid(int invoiceidparam) {     var invoice2 = null;     using (var db = new portalentities())     {         var invoices2 = b in db.invoices                         b.invoiceid == invoiceidparam                         select b;         invoice2 = toinvoicedto(invoices2.firstordefault());      }      return invoice2; } 

but navigation properties not getting listed when type invoice.invoiceservicexrefs..

how navigation properties correctly , create invoicedto object list<servicechargedto>?

you can use pretty same code map servicechargelineitems, used in initial query

private static invoicedto toinvoicedto(invoice invoice) {     invoicedto e = new invoicedto()     {         invoiceid = invoice.invoiceid,         invoicetotal = invoice.totalamount     };      e.servicechargelineitems = invoice.invoiceservicexrefs.                                select(b => new servicechargedto                                {                                    servicechargeid = b.servicechargeid,                                    quantity = b.servicecharge.qty,                                    unitprice = b.servicecharge.unitprice,                                    amount = b.servicecharge.amount                                }).tolist()      return e; } 

update:

following how called. note use of tolist() on invoicesquery. approach issues multiple queries.

var invoicesquery = in db.invoices              a.invoiceid == invoiceidparam             select a;  list<invoicedto>  listtest = invoicesquery.tolist().select(x => toinvoicedto(x)).tolist();