c# - WPF ListView not rendering properly -

i have created listview control display users connected application. working before added celltemplates gridviewcolumns. when add item list, not show up. however, if close , reopen list item appear. seems item being added properly, control not rendering after item added. code below. in advance assistance.

public class ncwindow {        public grid _grid;     public listview lstconnectedusers;               private gridview connectedusersgrid;      public list<connecteduseritem> roomusers = new list<connecteduseritem>();      public ncwindow(grid grid)     {                                _grid=grid;          setter setter = new setter();         setter.property = gridviewcolumnheader.visibilityproperty;         setter.value = visibility.collapsed;              style style = new style();         style.targettype = typeof(gridviewcolumnheader);                         style.setters.add(setter);                        style lcustyle = new style(typeof(listviewitem));         trigger lcutrigger = new trigger();         lcutrigger.property = listviewitem.isselectedproperty;         lcutrigger.value = true;         setter lcusetter = new setter(listviewitem.foregroundproperty,brushes.blue);          frameworkelementfactory textblockfactory = new frameworkelementfactory(typeof(textblock));         textblockfactory.setbinding(textblock.textproperty,new binding("username"));                     textblockfactory.setbinding(textblock.contextmenuproperty,new binding("menu"));                   datatemplate textblockdatatemplate = new datatemplate();         textblockdatatemplate.visualtree = textblockfactory;          frameworkelementfactory imagefactory = new frameworkelementfactory(typeof(image));         imagefactory.setbinding(image.sourceproperty,new binding("imgpath"));                     datatemplate imgdatatemplate = new datatemplate();         imgdatatemplate.visualtree = imagefactory;          gridviewcolumn statuscolumn = new gridviewcolumn();         statuscolumn.width = 10;         statuscolumn.celltemplate = imgdatatemplate;          gridviewcolumn usercolumn = new gridviewcolumn();         usercolumn.width = 100;         usercolumn.celltemplate = textblockdatatemplate;          gridviewcolumn clmuserid = new gridviewcolumn();         clmuserid.displaymemberbinding = new binding("userid");         clmuserid.width = 0;          connectedusersgrid = new gridview();         connectedusersgrid.columns.add(statuscolumn);            connectedusersgrid.columns.add(usercolumn);                                  connectedusersgrid.columns.add(clmuserid);           connectedusersgrid.columnheadercontainerstyle = style;                                    lstconnectedusers = nc.getnewlistview();//new listview();         lstconnectedusers.horizontalalignment = horizontalalignment.right;         lstconnectedusers.margin = new thickness(0,2,2,34);              lstconnectedusers.width = 130;               lstconnectedusers.view = connectedusersgrid;                         lstconnectedusers.selectionmode = selectionmode.single;         lstconnectedusers.itemcontainerstyle = lcustyle;         lstconnectedusers.itemssource = roomusers;          grid.children.add(lstconnectedusers);                        }                 public void addconnecteduser(clientaccess.svc.client user, clientaccess.svc.room room)     {         try         {                    usercontextmenu contextmenu = null;                          contextmenu = new usercontextmenu(nc,user);                                      contextmenu.opened += (sender,args) => contextmenu.onopen();                              connecteduseritem = new connecteduseritem(){ imgpath = "", username = user.username, userid = user.userid, menu = contextmenu};                                                                                                roomusers.insert(0,i);                                                                       }         catch(exception ex)         {          }     }      public void removeconnecteduser(clientaccess.svc.client user)     {         try         {             connecteduseritem = roomusers.find(delegate(connecteduseritem ii){return ii.userid==user.userid;});             roomusers.remove(i);         }         catch(exception ex)         {          }     }    }  public class connecteduseritem : inotifypropertychanged {     private string imgpath;     private string username;     private int userid;     private usercontextmenu menu;      public event propertychangedeventhandler propertychanged;      public string imgpath     {         { return imgpath; }         set { imgpath = value; onpropertychanged("imgpath"); }     }      public string username     {         { return username; }         set { username = value; onpropertychanged("username"); }     }      public int userid     {         { return userid; }         set { userid = value; onpropertychanged("userid"); }     }      public usercontextmenu menu     {         {  return menu; }         set { menu = value; }     }      protected void onpropertychanged(string propertyname)     {         if (propertychanged != null)                         propertychanged(this, new propertychangedeventargs(propertyname));               } }  public class usercontextmenu : contextmenu {     private clientaccess.svc.client client;     private menuitem misilence, miaddbuddy, miprivatemessage;      public usercontextmenu(clientaccess.svc.client _client)     {         client = _client;          misilence = new menuitem();                  misilence.header = "silence";         misilence.click += misilence_click;          miaddbuddy = new menuitem();                     miaddbuddy.header = "friends";         miaddbuddy.click += miaddbuddy_click;          miprivatemessage = new menuitem();                   miprivatemessage.header = "send message";                    miprivatemessage.click += miprivatemessage_click;          items.add(miprivatemessage);         items.add(miaddbuddy);         items.add(misilence);                            }      public void onopen()     {      }      private void misilence_click(object sender, routedeventargs e)     {                         }      private void miaddbuddy_click(object sender, routedeventargs e)     {                 }      private void miprivatemessage_click(object sender, routedeventargs e)     {                         } } 

use

private observablecollection<connecteduseritem> roomusers = new observablecollection<connecteduseritem>(); 

instead of

public list<connecteduseritem> roomusers = new list<connecteduseritem>(); 

if still doesn't work, can force refresh adding these lines after insert new item roomusers

var view = collectionviewsource.getdefaultview(itemssource); view.refresh();