asynchronous - How to read image from LocalFolder without using await in C#? -

i developing windows app. there model class property coversource of type imagesource , property filename of type string. both of them data bidden views can't make getters or setters async functions. want in setter of filename, async function called , after coversource set asynchronously reading file applicationdata.current.localfolder. newbie c# , little google. how write such async function , call callback, in javascript?

you have couple of conflicting requirements here. first, windows platform (just other modern mobile platform) requires view updates synchronous. blocking ui thread not considered acceptable; updates must immediate. secondly, reading file i/o-based operation, , naturally asynchronous. forces non-blocking approach.

the answer realize both requirements correct. ui must updated immediately, , file i/o must take arbitrary amount of time. so, proper design think ui looks while i/o in progress, , purposefully design scenario.

something should work:

public string filename {   { return filename; }   set   {     filename = value;     loadfileasync();   } }  private async task loadfileasync() {   try   {     coversource = ...; // "loading" image or something.     var image = await ...;     coversource = image;   }   catch (exception ex)   {     coversource = ...; // "error" image or something.   } } 

i have msdn article on async data binding goes more detail, , introduces notifytaskcompletion type takes care of lot of boilerplate code approach.