WPF ListView SelectedValue not being set -

i've looked @ few solutions nothing has worked yet me.

i'm using mvvm project , have listview can't set selecteditem property.

if (simplified) xaml.

<listview name="uxpackagegroups" itemssource="{binding path=packagegroups, updatesourcetrigger=propertychanged, mode=twoway}" borderthickness="0"       borderbrush="#ff0000e8" scrollviewer.cancontentscroll="true"       selecteditem="{binding path=packagegroupselecteditem, mode=twoway}" > <listview.itemtemplate>     <datatemplate>        <label content="{binding name}" height="20" margin="0" padding="0"/>     </datatemplate> </listview.itemtemplate> 

and bind packagegroups in viewmodel

   public packagegroup packagegroupselecteditem {get; set; }    public observablecollection<packagegroup> packagegroups {get; set; }     private void loadui()    {         packagegroups = factory.loadallpackagegroups())          // if try hard-code pre-selected item here doesn't work.         // 34 valid id , see valid object when stepping through code          packagegroupselecteditem = packagegroup.loadbyid(db, 34);    } 

anything glaring in code?

thanks.

one possible problem you're not implementing inotifypropertychanged in packagegroupselecteditem property.