private async Task OnShowContactDetails(ContactViewModel qvm)
{
SelectedContact = qvm;
await serviceLocator.Get <INavigationService>()
.NavigateAsync(AppPages.Detail);
}
private async Task OnEditContact(ContactViewModel contact)
{
SelectedContact = contact;
await serviceLocator.Get <INavigationService>()
.NavigateAsync(AppPages.Edit, contact);
}