c# - Get data from JSON, store in IsolatedStorageSettings.ApplicationSettings, retrieve data when JSON is retrieved -

i'm trying title says in windows phone 8 , here how go it:

private async void application_launching(object sender, launchingeventargs e) {     var settings = isolatedstoragesettings.applicationsettings;     settings.add("listofcurrency", await currencyhelpers.getjsoncurrency()); } 

in currencyhelpers:

    public async static task<dictionary<string, double>> getjsoncurrency()     {         httpclient client = new httpclient();          string jsonresult = await client.getstringasync("http://openexchangerates.org/api/latest.json?app_id=xxxxxxx");          jsoncurrency jsondata = jsonconvert.deserializeobject<jsoncurrency>(jsonresult);          dictionary<string, double> currencycollection = new dictionary<string, double>();          currencycollection = jsondata.rates;          return currencycollection;      } 

when mainpage loads, call method currencyhelpers:

    public static keyvaluepair<double, double> getstoragecurrencypairrates(string firstcurrency, string secondcurrency)     {         var settings = isolatedstoragesettings.applicationsettings;         double firstcurrencyrate = 1;         double secondcurrencyrate = 1;          dictionary<string, double> currencycollection = new dictionary<string,double>();          //needs code here check if "listofcurrency" has jsondata stored in it.          settings.trygetvalue<dictionary<string,double>>("listofcurrency", out currencycollection);          foreach (keyvaluepair<string, double> pair in currencycollection)         {             if (pair.key == firstcurrency)             {                 firstcurrencyrate = pair.value;             }              else if (pair.key == secondcurrency)             {                 secondcurrencyrate = pair.value;             }          }          return new keyvaluepair<double, double>(firstcurrencyrate, secondcurrencyrate);               } } 

the idea want store json data storage, retrieve when available, ideas? appreciated!

the way thinking await , async correct destroyed concept calling method when page loads. wilfred wee said wrong.

the correct way declare event handler in app.xamls.cs this:

public event eventhandler<bool> settingsready;

then change application_launching() method following:

private async void application_launching(object sender, launchingeventargs e) {     var settings = isolatedstoragesettings.applicationsettings;     settings.add("listofcurrency", await currencyhelpers.getjsoncurrency());      if (settingsready!= null)         settingsready(this, true); } 

and in mainpage.xaml.cs (constructor - not when loaded) declare call function called when data ready:

    // constructor     public mainpage()     {         initializecomponent();          // call functions         app.settingsready += app_settingsready;     }      void app_settingsready(object sender, bool e)     {         // here call function further data processing         getstoragecurrencypairrates();     }