How can i set entry field text/value from (Rg.Plugins.Popup) page?

In my project i have use Rg.Plugins.Popup for popup.In the custom popup page one list view available.
But problem is I'm unable to set selected list item name into Entry field parent xaml.cs.

Popuppage: PopupList.Xaml
PopupList.Xaml.cs
to set data MainPage.xaml
MainPage.xaml.cs

MainPage.xaml is parent view
PopupList.Xaml is child view.