c# - Search function LINQ. Use checkbox values as parameters -

i have search function tales 7 parameters , 6 of them checkbox values. bools shown down below. have problem datetime search. if user check box if run serach function date not null in database. code @ moment. feedback how improve code better performance , code structure.

public list<invoice> getallinvoicesbysearch(int merchant, long buyer, bool send, bool paid, bool firstreminder, bool secondreminder, bool invoiceclaim)     {         var sendvalue = new invoicestatus();         var paidvalue = new invoicestatus();         var firstremind = new datetime();         var secondremind = new datetime();         if (buyer <= 0)         {             return null;         }         if (send)         {              sendvalue = invoicestatus.sent;         }         if (paid)         {             paidvalue = invoicestatus.paid;         }         if (firstreminder)         {             firstremind = datetime.now;         }         if (secondreminder)         {             secondremind = datetime.now;         }          return             context.invoices.where(                 =>                    i.installationid == merchant && i.buyer.msisdn == buyer || i.status == sendvalue || i.status == paidvalue ||                     i.firstreminderdate == firstremind || i.secondreminderdate == secondremind).tolist();     } 

so problem datetime @ moment correctly. suggestions on how solve problem , improve code?

you better off using predicatebuilder , converting extension method this:

public static class extensionmethods {     public static iqueryable<invoice> search(this iqueryable<invoice> src, int merchant,         long buyer, bool send, bool paid, bool firstreminder,         bool secondreminder, bool invoiceclaim)     {         var predicate = predicatebuilder.false<invoice>();         var sendvalue = new invoicestatus();         var paidvalue = new invoicestatus();         var firstremind = new datetime();         var secondremind = new datetime();         if (buyer <= 0)         {             return src.where(predicate);         }         predicate=predicate.or(i=>i.installationid == merchant && i.buyer.msisdn == buyer);         if (send)         {              predicate=predicate.or(i=>i.status == invoicestatus.sent);         }         if (paid)         {             predicate=predicate.or(i=>i.status == invoicestatus.paid);         }         if (firstreminder)         {             predicate=predicate.or(i=>i.firstreminderdate == datetime.today);         }         if (secondreminder)         {             predicate=predicate.or(i=>i.secondreminderdate == datetime.today);         }         return src.where(predicate);     } } 

also, if understand code correctly, invoicestatus should either enum, or @ least, invoicestatus.sent , invoicestatus.paid should marked being static. reference so:

context.invoices.search(...).orderby(...)...

it make further manipulation easier if need sorting, paging, filtering beyond original searching.