c# - Windows store app crashes when no internet -

i creating first windows store app , have several web service calls during startup , periodically through app. have noticed app ot start/crashes or closes down when don't have internet access because of web serivice calls. want app start in normal way initial data , seem normal when there no internet access. data webservice weather data show in various textboxes , graphs.

the code below shows webservice calls in extended splash screen.

public sealed partial class extendedsplashscreen : page {  //parameteritem max1dayago = new parameteritem(); //parameteritem min1dayago = new parameteritem();   public extendedsplashscreen() {     this.initializecomponent(); }  /// <summary> /// invoked when page displayed in frame. /// </summary> /// <param name="e">event data describes how page reached.  parameter /// property typically used configure page.</param> protected override async void onnavigatedto(navigationeventargs e) {      string[] periodselector = { "1dayago", "1weekago", "1monthago" };     string[] modeselector = { "max", "min" };     string[] parameterselector = { "umttemp1", "umtwindspeed", "umtadjbarompress", "umtrainrate" };       //create webservice object     servicereference.webservicesoapclient webserviceobj = new servicereference.webservicesoapclient();     //first create object holds max data yesterday     var getmax1dayagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[0], modeselector[0]);      //create object holds min data yesterday      var getmin1dayagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[0], modeselector[1]);     //save arrayofvalue , arrayofunit parameteritem object. these objects created during startup     // , can accessed , updated methods in page later see maxminbutton_click method     //for maxminbutton use these data      //create object holds max data last week     var getmax1wekagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[1], modeselector[0]);     //create object holds min data last week     var getmin1wekagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[1], modeselector[1]);     //create object holds max data last month     var getmax1monthagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[2], modeselector[0]);     //create object holds min data last month     var getmin1monthagoobj = await webserviceobj.getselectedmaxmindataasync(parameterselector, periodselector[2], modeselector[1]);       (app.current app).max1dayago.arrayofvalue = getmax1dayagoobj.arrayofvalue;     (app.current app).max1dayago.arrayofunit = getmax1dayagoobj.arrayofunit;      (app.current app).min1dayago.arrayofvalue = getmin1dayagoobj.arrayofvalue;     (app.current app).min1dayago.arrayofunit = getmin1dayagoobj.arrayofunit;       (app.current app).max1weekago.arrayofvalue = getmax1wekagoobj.arrayofvalue;     (app.current app).max1weekago.arrayofunit = getmax1wekagoobj.arrayofunit;      (app.current app).min1weekago.arrayofvalue = getmin1wekagoobj.arrayofvalue;     (app.current app).min1weekago.arrayofunit = getmin1wekagoobj.arrayofunit;      (app.current app).max1monthago.arrayofvalue = getmax1monthagoobj.arrayofvalue;     (app.current app).max1monthago.arrayofunit = getmax1monthagoobj.arrayofunit;      (app.current app).min1monthago.arrayofvalue = getmin1monthagoobj.arrayofvalue;     (app.current app).min1monthago.arrayofunit = getmin1monthagoobj.arrayofunit;       string[] startupdata = new string[13];       startupdata[0] = " " + (app.current app).max1dayago.arrayofvalue[0] + " " + (app.current app).max1dayago.arrayofunit[0]; //    maxtemp      startupdata[1] = " " + (app.current app).max1dayago.arrayofvalue[1] + " " + (app.current app).max1dayago.arrayofunit[1]; //    maxwindsped      startupdata[2] = " " + (app.current app).max1dayago.arrayofvalue[2] + " " + (app.current app).max1dayago.arrayofunit[2]; //    maxairpressure      startupdata[3] = " " + (app.current app).max1dayago.arrayofvalue[3] + " " + (app.current app).max1dayago.arrayofunit[3];//     maxrainfall      startupdata[4] = " " + (app.current app).min1dayago.arrayofvalue[0] + " " + (app.current app).min1dayago.arrayofunit[0]; //    mintemp      startupdata[5] = " " + (app.current app).min1dayago.arrayofvalue[1] + " " + (app.current app).min1dayago.arrayofunit[1];//     minwindsped      startupdata[6] = " " + (app.current app).min1dayago.arrayofvalue[2] + " " + (app.current app).min1dayago.arrayofunit[2];//     minairpressure       startupdata[7] = " " + (app.current app).min1dayago.arrayofvalue[3] + " " + (app.current app).min1dayago.arrayofunit[3];//     minrainfall        // main fields     // servicereference.webservicesoapclient webserviceobj = new servicereference.webservicesoapclient();     var getlatesttempobj = await webserviceobj.getlatestdataasync("umttemp1");     var getlatestwindobj = await webserviceobj.getlatestdataasync("umtwindspeed");     var getlatestwinddirobj = await webserviceobj.getlatestdataasync("umtadjwindir");     var getlatestairpressureobj = await webserviceobj.getlatestdataasync("umtadjbarompress");      startupdata[8] = " " + getlatesttempobj.value + " " + getlatesttempobj.unit;//temperaturemaintxtblock.text     startupdata[9] = " " + getlatestwindobj.value + " " + getlatestwindobj.unit;//temperaturemaintxtblock.text      startupdata[10] = "" + getlatestwinddirobj.value; //temperaturemaintxtblock.text      startupdata[11] = " " + getlatestairpressureobj.value + " " + getlatestairpressureobj.unit;//temperaturemaintxtblock.text      startupdata[12] = "last update: " + getlatestwinddirobj.timestamp;//temperaturemaintxtblock.text     //save startup data global variables     (app.current app).navigatedata = startupdata;        this.frame.setnavigationstate(e.parameter string);     this.frame.navigate(typeof(mainpage)); } } 

an approach have in of our team based apps prior call return data of net, network status checked. example:

  async task refreshfromweb(...) {     if (!app.hasinternetaccess)     {         await new windows.ui.popups.messagedialog(strings.nointernetwarning).showasync();         return;     }      //attempt access here }  public static bool hasinternetaccess {         {         var profile = windows.networking.connectivity.networkinformation.getinternetconnectionprofile();         if (profile == null)             return false;         return profile.getnetworkconnectivitylevel() ==                 windows.networking.connectivity.networkconnectivitylevel.internetaccess;     } }  

we took approach @ times similar uses await , returns true or false (the same done above, approach above gives dialog)

 public static async system.threading.tasks.task hasinternet() {     var profile = windows.networking.connectivity.networkinformation.getinternetconnectionprofile();     var hasnetaccess = profile != null;     if (!hasnetaccess)         await new windows.ui.popups.messagedialog(             content: infohub.apphubviewmodel.strings.nointernetwarning,             title: infohub.apphubviewmodel.strings.nointernetwarning).showasync();     return hasnetaccess; }  async void yourcontrolevent_click(object sender, itemclickeventargs e) {     //if net access, stuff, otherwise ignore     if (await isinternet())     {         //do net calls here     } }