vb.net - WPF binding with .NET object not communicating the data -

i following tutorial on wpf data binding. trying bind .net object's property xaml control control not display expected data. these believe relevant sections of code:

in procedural code: (note: removed observablecollection in photogallery after original post)

namespace photogallery partial public class mainwindow   inherits window   private photos new photos   ... end class  namespace photogallery public class photos   inherits collection(of photo)   ... end class 

in xaml (solution/project name ch13-photogallery):

<window x:class="photogallery.mainwindow"     ...     xmlns:local="clr-namespace:ch13_photogallery.photogallery"     ...>  <window.resources>   <local:photos x:key="photos"/> </window.resources> 

and control not displaying data, size of photos collection:

<label x:name="numitemslabel" background="aliceblue" fontsize="8" content="{binding source={staticresource photos}, path=count}"/> 

when typed in < label >, intellisense popped 'count' path property, think tells me have defined correctly.

if add line of procedural code behind refresh() method:

numitemslabel.content = photos.count 

then count displayed correctly.

but i'm not getting binding in xaml display photos.count.

this creates new instance of photos class:

<local:photos x:key="photos"/> 

if want bind photos collection have created in mainwindow.xaml.vb file should expose public property - can bind properties not fields - , set datacontext of window instance of class property defined, i.e. window class in case:

class mainwindow     public property photos photos      public sub new()          ' call required designer.         initializecomponent()         datacontext = me         ...     end sub end class 

you can bind directly property:

<label x:name="numitemslabel" background="aliceblue" fontsize="8" content="{binding path=photos.count}"/>