c# .net grid app search page -

trying use guide https://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh868180.aspx

my app contains personal trainers, , personal trainers have customers. want able search customers.

this how far am: can search customers on first/lastname , how many results there are, ie results(3), not show them.

i've included data:

using personaltrainergridapp.data; 

the if statement in navigationhelper_loadstate confusing me, i'm not sure have in it, , i'm not sure if filter_checked correct.

anyone have pointers? formatting!

private async void navigationhelper_loadstate(object sender, loadstateeventargs e)     {         var querytext = e.navigationparameter string;         // initialize results list.         allresultscollection = new dictionary<string, ienumerable<sampledatasource>>();          // keep track of number of matching items.          var totalmatchingitems = 0;         var filterlist = new list<filter>();         var groups = await sampledatasource.getpersonaltrainerasync();          foreach (var group in groups)         {             var matchingitems = group.customers.where(                 item =>                      item.firstname.indexof(                         querytext, stringcomparison.currentcultureignorecase) > -1 || item.lastname.indexof(                         querytext, stringcomparison.currentcultureignorecase) > -1 );              int numberofmatchingitems = matchingitems.count();             totalmatchingitems += numberofmatchingitems;             if (numberofmatchingitems > 0)             {                 allresultscollection.add(group.customers, matchingitems);                 filterlist.add(new filter(group.customers, numberofmatchingitems));             }          }          // create entry "all" viewing search results.          filterlist.insert(0, new filter("all", totalmatchingitems, true));          // communicate results through view model         this.defaultviewmodel["querytext"] = '\"' + querytext + '\"';         this.defaultviewmodel["filters"] = filterlist;         this.defaultviewmodel["showfilters"] = true;      }      /// <summary>     /// invoked when filter selected using radiobutton when not snapped.     /// </summary>     /// <param name="sender">the selected radiobutton instance.</param>     /// <param name="e">event data describing how radiobutton selected.</param>     void filter_checked(object sender, routedeventargs e)     {         // retrieve data context of sender (the selected radio button).         // gives selected filter object.          var filter = (sender frameworkelement).datacontext filter;          // mirror change collectionviewsource.         // not needed.         if (filtersviewsource.view != null)         {             filtersviewsource.view.movecurrentto(filter);         }          // determine filter selected         if (filter != null)         {             // mirror results corresponding filter object allow             // radiobutton representation used when not snapped reflect change             filter.active = true;              // todo: respond change in active filter setting this.defaultviewmodel["results"]             //       collection of items bindable image, title, subtitle, , description properties              if (filter.name.equals("all"))             {                 var tempresults = new list<sampledatasource>();                  // add items each group temporary results                 // list.                  foreach (var group in allresultscollection)                 {                     tempresults.addrange(group.value);                  }                  // display items.                 this.defaultviewmodel["results"] = tempresults;             }             else if (allresultscollection.containskey(filter.name))             {                 this.defaultviewmodel["results"] =                   new list<sampledatasource>(allresultscollection[filter.name]);             }              // ensure results found             object results;             icollection resultscollection;             if (this.defaultviewmodel.trygetvalue("results", out results) &&                 (resultscollection = results icollection) != null &&                 resultscollection.count != 0)             {                 visualstatemanager.gotostate(this, "resultsfound", true);                 return;             }         }          // display informational text when there no search results.         visualstatemanager.gotostate(this, "noresultsfound", true);     } 

thanks in advance, appreciated :-)