c# - How can I catch a bound data updated event? -

i writing app windows 8 , have ui class called groupeditemspage inherits layoutawarepage contains data :

 this.defaultviewmodel["groups"] = sampledatagroups; 

each item in sampledatagroups binded tile in ui , sampledatagroups class inherits bindablebase , each property set using

set{this.setproperty(ref this._property, value); } 

what able catch general event in ui class groupeditemspage each time property in sampledatagroups changed (so can rewrite sampledatagroups file). i've done research , i've found how notify event caught sampledatagroups, not if want sampledatagroups notify groupeditemspage?

your page should not writing data file. it's more of duty of view model or model rather. if have though need subscribe propertychanged event declared type of sampledatagroups variable , handle event in page object.