c# - Observable collection not reacting to it's collecion -

my listbox doesn't react observablecollection.

this listbox talking about.

<listbox x:name="createfieldslist"          horizontalalignment="left"          height="218"          verticalalignment="top"          width="244"          margin="0,86,0,0"          borderbrush="#ffb9b9b9">     <listbox.itemtemplate>         <datatemplate>             <grid margin="4"                   width="215"                   height="32.96"                   background="white">                 <textblock text="{binding name}"                            fontweight="normal"                            fontsize="18.667"                            padding="8,3,0,0" />             </grid>         </datatemplate>     </listbox.itemtemplate> </listbox> 

in mainwindow, prepare data binding this

private observablecollection<fieldlistitem> _fielditems;  public mainwindow() {     initializecomponent();     _fielditems = new observablecollection<fieldlistitem>();     createfieldslist.itemsource = _fielditems; } 

a fieldlistitem following

public class fieldlistitem : viewitem {     private field _field;     public string name     {         { return _field.name; }     }      public string value     {         { return _field.value; }     }      public fieldlistitem(field f)     {         _field = f;                } } 

and viewitem

public class viewitem : inotifypropertychanged {     private event propertychangedeventhandler propertychanged;      protected void raisepropertychanged([callermembername] string caller = "")     {         if (propertychanged != null) propertychanged(this, new propertychangedeventargs(caller));     }      //the interface forces me implement this. why?     event propertychangedeventhandler inotifypropertychanged.propertychanged     {         add { }         remove { }     } } 

i don't know why isn't working. please help?

the inotifypropertychanged interface needs implement event. event implementation not work because registrations , deregistrations ignored because add , remove blocks empty.

implement event without add , remove:

public class viewitem : inotifypropertychanged {     public event propertychangedeventhandler propertychanged;      protected void raisepropertychanged([callermembername] string caller = "")     {         var copy = propertychanged;         if (copy != null)              copy(this, new propertychangedeventargs(caller));     } }