c# - How to update an image on a page in UWP? -

i've got gridviewitem. gridviewitem has background imagebrush. want change imagebrush new source when clicking button.

for i'm using:

blck.background = new imagebrush(new bitmapimage(new uri("ms-appx:///assets/sensorbg.png"))); 

it work new image shows whenever click on corresponding gridviewitem. can tell me how update without having click on gridviewitem?

i've tried put within block no success:

            coreapplication.mainview.corewindow.dispatcher.runasync(coredispatcherpriority.normal,             () =>             {                 blck.background = new imagebrush(new bitmapimage(new uri("ms-appx:///assets/sensorbg.png")));             }             ); 

the best be, if have defined itemclass suitable properties , implement inotifypropertychanged - appropriate binding, every change update ui. here small sample - xaml:

<stackpanel>     <button content="change background of second item" click="button_click"/>     <gridview background="{themeresource applicationpagebackgroundthemebrush}" itemssource="{x:bind items}">         <gridview.itemtemplate>             <datatemplate x:datatype="local:itemclass">                 <border>                     <border.background>                         <imagebrush imagesource="{x:bind image, mode=oneway}"/>                     </border.background>                     <textblock text="{x:bind name}"/>                 </border>             </datatemplate>         </gridview.itemtemplate>     </gridview> </stackpanel> 

and code behind:

public sealed partial class mainpage : page {     public list<itemclass> items = new list<itemclass>();      public mainpage()     {         items.add(new itemclass { name = "first item", image = new bitmapimage(new uri("ms-appx:///assets/storelogo.png")) });         items.add(new itemclass { name = "second item", image = new bitmapimage(new uri("ms-appx:///assets/storelogo.png")) });         this.initializecomponent();     }      private void button_click(object sender, routedeventargs e) => items[1].image = new bitmapimage(new uri("ms-appx:///test.jpg")); }  public class itemclass : inotifypropertychanged {     public event propertychangedeventhandler propertychanged;     private void raiseproperty(string name) => propertychanged?.invoke(this, new propertychangedeventargs(name));      private imagesource image;     public imagesource image     {         { return image; }         set { image = value; raiseproperty(nameof(image)); }     }      public string name { get; set; } }