Disable Selection For Particular Items

<listView:SfListView x:Name="listView" ItemSize="70" ItemsSource="{Binding contactsinfo}" 
                      ItemSpacing="0,0,5,0" SelectionMode="Multiple">
    <listView:SfListView.Behaviors>
        <local:Behavior/>
    </listView:SfListView.Behaviors>

    <listView:SfListView.ItemTemplate>
        <DataTemplate>
            <ViewCell>
                <ViewCell.View>
                    <code>
                    . . .
                    . . .
                    <code>
                </ViewCell.View>
            </ViewCell>
        </DataTemplate>
    </listView:SfListView.ItemTemplate>
</listView:SfListView>

public partial class MainPage : ContentPage
{
  public MainPage()
  {
    InitializeComponent();
  }

  private void listView_SelectionChanging(object sender, Syncfusion.ListView.XForms.ItemSelectionChangingEventArgs e)
  {
  if (e.AddedItems.Count > 0 && (e.AddedItems[0] as Contacts).Category == "Non-Selectable items")
      e.Cancel = true;
  }
}