protected override _View ResolveInternalItemsPanel(_View itemsPanel)
{
// If the items panel is a virtualizing panel, we substitute it with NativeListViewBase
var virtualizingPanel = itemsPanel as IVirtualizingPanel;
if (virtualizingPanel != null)
{
var layouter = virtualizingPanel.GetLayouter();
layouter.ShouldApplyChildStretch = ShouldApplyChildStretch;
PrepareNativeLayout(layouter);
var panel = new NativeListViewBase();
panel.XamlParent = this;
panel.NativeLayout = layouter;
panel.BindToEquivalentProperty(virtualizingPanel, "Background");
InitializeNativePanel(panel);
return(panel);
}
else
{
// Otherwise act as a normal ItemsControl
return(base.ResolveInternalItemsPanel(itemsPanel));
}
}
partial void CleanUpNativePanel(NativeListViewBase panel)
{
_headerFooterSubscription.Disposable = null;
panel.NativeLayout?.RemoveAllViews();
panel.ViewCache?.OnUnloaded();
panel.NativeLayout = null;
panel.SetViewCacheExtension(null);
panel.CurrentAdapter = null;
}
protected override _View ResolveInternalItemsPanel(_View itemsPanel)
{
// If the items panel is a virtualizing panel, we substitute it with NativeListViewBase
var virtualizingPanel = itemsPanel as IVirtualizingPanel;
if (virtualizingPanel != null)
{
var internalPanel = new NativeListViewBase();
var layouter = virtualizingPanel.GetLayouter();
PrepareNativeLayout(layouter);
internalPanel.NativeLayout = layouter;
internalPanel.BindToEquivalentProperty(virtualizingPanel, "Background");
return(internalPanel);
}
else
{
// Otherwise act as a normal ItemsControl
return(base.ResolveInternalItemsPanel(itemsPanel));
}
}
private void InitializeNativePanel(NativeListViewBase panel)
{
var source = new ListViewBaseSource(panel);
panel.Source = source;
panel.NativeLayout.Source = new WeakReference <ListViewBaseSource>(panel.Source);
BindToPanel(panel, nameof(ItemsSource));
panel.AnimateScrollIntoView = AnimateScrollIntoView;
var disposables = new CompositeDisposable();
Action headerFooterCallback = () => panel?.UpdateHeaderAndFooter();
RegisterCallback(HeaderProperty, headerFooterCallback).DisposeWith(disposables);
RegisterCallback(HeaderTemplateProperty, headerFooterCallback).DisposeWith(disposables);
RegisterCallback(FooterProperty, headerFooterCallback).DisposeWith(disposables);
RegisterCallback(FooterTemplateProperty, headerFooterCallback).DisposeWith(disposables);
_callbackSubscriptions.Disposable = disposables;
}
public ListViewBaseSource(NativeListViewBase owner)
{
Owner = owner;
}
public BufferViewCache(NativeListViewBase owner)
{
_owner = owner;
}
public SnapPointsSnapHelper(NativeListViewBase owner)
{
_owner = owner;
}
private void InitializeNativePanel(NativeListViewBase panel)
{
panel.CurrentAdapter = new NativeListViewBaseAdapter {
Owner = panel
};
}
/// <summary>
/// Bind a property on the native collection panel to its equivalent on ListViewBase
/// </summary>
private void BindToPanel(NativeListViewBase panel, string propertyName, BindingMode bindingMode = BindingMode.OneWay)
{
panel.Binding(propertyName, propertyName, this, bindingMode);
}
partial void CleanUpNativePanel(NativeListViewBase panel)
{
_callbackSubscriptions.Disposable = null;
panel.Source?.Dispose();
panel.Source = null;
}
public ScrollingViewCache(NativeListViewBase owner)
{
_owner = owner;
}
partial void CleanUpNativePanel(NativeListViewBase panel);