c# - Button click doesn't lead to Listview to update it's value -

very simple situation quite stuck here. in past have worked in teams written mvvm architecture codes, literately first little program trying write using mvvm arch. ground up.

i have button fires method called find(). , part works fine. have set binding listview read data find() method going change.

code snippets followed:

    public icommand findbluetoothcommand     {                 {             if (_findbluetoothcommand == null)             {                 _findbluetoothcommand = new relaycommand(param => find());             }             return _findbluetoothcommand;         }     }      public observablecollection<bluetoothdeviceinfo> discovereddeviceslist     {                 {             return this._discoverddeviceslist;         }         set         {             this._discoverddeviceslist = value;             base.onpropertychanged("discovereddeviceslist");         }      }      private observablecollection<bluetoothdeviceinfo> _discoverddeviceslist;      #endregion //presentation properties 

my find() method

   public void find()     {           bool inrange;         guid fakeuuid = new guid("{f13f471d-47cb-41d6-9609-bad0690bf891}");          // specially created value, no matches.         var cli = new bluetoothclient();          //bluetoothdeviceinfo[] device = cli.discoverdevices();         //_discoverddeviceslist = new observablecollection<bluetoothdeviceinfo[]>();         _discoverddeviceslist = new observablecollection<bluetoothdeviceinfo>(cli.discoverdevices());        .        .        .      } 

and xaml code

<window x:class="bluetooth_tester_mvvm.mainwindow"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     title="blue tooth tester v1.0" height="350" width="525"> <window.resources>     <collectionviewsource         x:key="devicelist"         source="{binding path=discovereddeviceslist}">      </collectionviewsource> </window.resources> <grid>     <grid.rowdefinitions>         <rowdefinition height="250"></rowdefinition>         <rowdefinition height="auto"></rowdefinition>     </grid.rowdefinitions>     <listview          grid.row="0"          datacontext="{staticresource devicelist}"         itemssource="{binding}">                 </listview>     <button grid.row="1" content="button" command="{binding path=findbluetoothcommand}" horizontalalignment="right" verticalalignment="top" width="75" margin="5"/>  </grid> 

in process if put find() in viewmodel's constructor can see list of devices. when go way want program work, when button pressed, using break point can see `_discoverddeviceslist' getting updated , filled values doesn't make it's way listview should. seems binding doesn't sense change happened variable.

would nice if give me hand on this.

cheers

instead of

_discoverddeviceslist = new observablecollection<bluetoothdeviceinfo>(cli.discoverdevices()); 

you should do

  discovereddeviceslist= new observablecollection<bluetoothdeviceinfo>(cli.discoverdevices()); 

otherwise onpropertychanged() not fired.

and better initialize collection once , use clear, add , remove alter it.

 discovereddeviceslist.clear()  foreach(var item in cli.discoverdevices())     discovereddeviceslist.add(item);