C# & WPF Data Binding to ObservableCollection -

i came linux heavy environment, wrote of tools in python in windows heavy environment, , need share tools team , need gui driven trying learn c#/wpf. i'm getting confused on data binding observablecollection in code behind. can work, don't understand why, bothers me.

my code simple, , literally trying basics working can move on more complicated parts:

xaml:

<listview x:name="lvurllist" horizontalalignment="left" height="441" margin="15,62,0,0" verticalalignment="top" width="486" selectionchanged="listview_selectionchanged" itemssource="{binding path=urllist, elementname=mainwindow1}">         <listview.itemtemplate>             <datatemplate>                 <wrappanel>                     <textblock text="{binding domain}"/>                 </wrappanel>             </datatemplate>         </listview.itemtemplate>     </listview> 

code behind:

namespace referalscraper {     /// <summary>     /// interaction logic mainwindow.xaml     /// </summary>     public partial class mainwindow : window     {          //public observablecollection<url> urllist { get; set; } // method 1         public observablecollection<url> urllist = new observablecollection<url>(); // method 2         public mainwindow()         {             // urllist = new observablecollection<url>(); // method 1             initializecomponent();             urllist.add(new url() { domain = "www.test1.com" });          }          public class url         {             public string domain { get; set; }          }          private void button_click(object sender, routedeventargs e)         {              urllist.add(new url() { domain = "www.test2.com" });             urllist.add(new url() { domain = "www.test3.com" });          }     } } 

the uncommented method creating , instantiating observablecollection doesn't work, code compiles output error:

system.windows.data error: 40 : bindingexpression path error: 'urllist' property not found on 'object' ''mainwindow' (name='mainwindow1')'. bindingexpression:path=urllist; dataitem='mainwindow' (name='mainwindow1'); target element 'listview' (name='lvurllist'); target property 'itemssource' (type 'ienumerable') 

which understand means can't find urllist object in mainwindow. don't understand why can't find it.

if switch method 1 , uncomment following 2 lines (and comment out "method 2" part) works fine:

public observablecollection<url> urllist { get; set; } ... public mainwindow(){        urllist = new observablecollection<url>() 

why declaring observerablecollection { get; set } needed? don't quite grasp why can't instantiate observablecollection empty observerablecollection in method 2.

i'm feeling incredibly dense, , haven't quite been able track down right terminology close answering questions. can explain not bright fellow missing?

i have feeling c# understanding missing.

the { get; set; } syntax defines urilist property (an auto-implemented property, in case ). without this, urilist field.

wpf data binding cannot bind fields. see this related question further discussion why case.

generally in c# fields not exposed public, properties preferred. allows change get/set implementation if required. aside, naming convention properties pascalcased (so urilist rather urilist).