Listview is not populating after navigation

I have listview defined in xaml as below:
<ListView x:Name="Iv" ItemSelected="Iv_ItemSelected" ItemsSource="{Binding deviceListEx}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label Text="{Binding .}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

This does work in first page load, however in ios platform when I navigate to another page then back to the listview page by clicking back button, the page is blank, means listview is not populated.
Application is in c# and working fine in android.

Have anyone faced such issue or similar issue? Do let me know how can I solve this.