c# - Autofill with REST API in windows 8.1 phone app -

i implementing city search want autofill functionality when select city want id sent api. populate other fields.

 private async void autosuggestbox_textchanged(autosuggestbox sender, autosuggestboxtextchangedeventargs args)         {             if (args.reason == autosuggestionboxtextchangereason.userinput)             {                 string text = sender.text;                  if (text.length >= 3)                 {                    getcities(text);                    sender.itemssource = await task<string[]>.run(() => { return this.getsuggestions(text); });                 }                 else                 {                     sender.itemssource = new string[] { "no suggestions..." };                 }             }         } 

my response class

private async void getcities(string city)         {             try             {                 string baseaddress = url.url + "searchcities?q="+city+"&access_token=" + tcm;                  httpclient httpclient = new httpclient();                  string co = "";                 var content = await httpclient.getasync(new uri(baseaddress));                 if (!content.issuccessstatuscode)                 {                     tokengenerator tc = new tokengenerator();                     tc.gettoken();                     tcm = tokenmanager.accesst.access_tocken;                      httpclient client = new httpclient();                     content = await client.getasync(new uri(baseaddress));                  }                  co = await content.content.readasstringasync();                 autofillhelper result = jsonconvert.deserializeobject<autofillhelper>(co);                                    foreach (var item in result.data)                 {                    suggestions = new string [] {item.city} ;                 }              }             catch (exception ex)             {                 dispatchertimer.stop();                 throw new exception(ex.tostring());             }         }     private string[] getsuggestions(string text)         {             string[] result = null;              result = suggestions.where(x => x.startswith(text)).toarray();              return result;         } 

my set

class autofill     {                         public string city_id { get; set; }             public string city { get; set; }              }       class autofillhelper     {         public list<autofill> data { get; set; }                  } 

i want display response api person select it. run time error thrown. can please guide me has gone wrong.

any kind of appreciated...