windows phone 8 - Telerik RadDataBoundListBox Reset -

how can reset or delete old data in telerik raddataboundlistbox json parse , display in raddataboundlistbox

raddataboundlistbox load old data every time, if click button load new data want delete or reset old data becouse every time displaying old data

public void getmaindata()         {              string mainurldata = "http://www.mydomain.com/app.json";              webclient wc = new webclient();             wc.downloadstringcompleted += wc_downloadstringcompleted;             wc.downloadstringasync(new uri(mainurldata));            }           void wc_downloadstringcompleted(object sender, downloadstringcompletedeventargs e)         {             try             {                 string result = e.result.tostring();                 jsonconvert.populateobject(result, populatedata);                 newslist.itemssource = populatedata;             }        } 

little late, hope helps..

with mvvmlight

use httpclient:

    public async task<observablecollection<t>> getall()     {         var client = new httpclient();          client.defaultrequestheaders.accept.add(mediatypewithqualityheadervalue.parse(jsonmediatype));         //if (usetoken)         //client.defaultrequestheaders.authorization = new authenticationheadervalue("bearer", token);          var json = await client.getstringasync(string.format("{0}{1}{2}", apiurl, addresssuffix, apikey)).configureawait(false);          debug.writeline(json);          jobject o = jobject.parse(json);          debug.writeline(o);          return await task.factory.startnew(() => jsonconvert.deserializeobject<observablecollection<t>>(o[modulename].tostring()));     } 

itemsource:

private observablecollection<ticket> _mytickets;      public observablecollection<ticket> mytickets     {                 {             return _mytickets;         }         set         {             _mytickets = value;              raisepropertychanged(() => mytickets);         }     } 

telerik radboundlistbox:

<telerikprimitives:raddataboundlistbox                  x:name="raddataboundlistbox"                 itemssource="{binding ticketlist}"                 itemtemplate="{staticresource listboxitemtemplate}"                 itemcontainerstyle="{staticresource itemcontainerstyle}"                 selecteditem="{binding selectedticket, mode=twoway}"                 horizontalalignment="stretch"                 verticalalignment="stretch"                 height="750"                 scrollviewer.verticalscrollbarvisibility="auto"                 useoptimizedmanipulationrouting="false"                 emptycontent="laden..."                 ispulltorefreshenabled="true">             <i:interaction.triggers>                 <i:eventtrigger eventname="refreshrequested">                     <cmd:eventtocommand                          command="{binding refreshrequested}"/>                 </i:eventtrigger>             </i:interaction.triggers>         </telerikprimitives:raddataboundlistbox> 

refresh command:

    private relaycommand _refreshcommand;      public relaycommand refreshrequested     {                 {             return _refreshcommand                 ?? (_refreshcommand = new relaycommand(                                       () =>                                       {                                           executerefreshcommand();                                       }));         }     }  public async void executerefreshcommand()     {             var tickets = await _dataservice.getall();              if (tickets != null)             {                 _ticketlist.clear();                  foreach (var ticket in tickets)                 {                     _ticketlist.add(ticket);                     debug.writeline(ticket.name);                 }                  messenger.default.send(new handleviewmessage() { stoppulltorefresh = true });                  raisepropertychanged(() => ticketlist);             }     }