private void FilterItem(string filter)
{
PatientsList.BeginRefresh();
if (string.IsNullOrEmpty(filter))
{
PatientsList.ItemsSource = patientItems;
}
else
{
PatientsList.ItemsSource = patientItems.Where(p => p.FirstName.ToLower().Contains(filter.ToLower()) || p.LastName.ToLower().Contains(filter.ToLower()));
}
PatientsList.EndRefresh();
}
