Ejemplo n.º 1
0
        public void UpdatePin(UIElement element, bool addPin)
        {
            var parent = CachedVisualTreeHelpers.GetParent(element);
            var child  = (DependencyObject)element;

            while (parent != null)
            {
                if (parent is ItemsRepeater repeater)
                {
                    var virtInfo = ItemsRepeater.GetVirtualizationInfo(child as UIElement);
                    if (virtInfo.IsRealized)
                    {
                        if (addPin)
                        {
                            virtInfo.AddPin();
                        }
                        else if (virtInfo.IsPinned)
                        {
                            if (virtInfo.RemovePin() == 0)
                            {
                                // ElementFactory is invoked during the measure pass.
                                // We will clear the element then.
                                repeater.InvalidateMeasure();
                            }
                        }
                    }
                }

                child  = parent;
                parent = CachedVisualTreeHelpers.GetParent(child);
            }
        }
Ejemplo n.º 2
0
        private void OnHideAnimationCompleted(ElementAnimator sender, UIElement element)
        {
            if (CachedVisualTreeHelpers.GetParent(element) == (DependencyObject)(m_owner))
            {
                m_owner.ViewManager.ClearElementToElementFactory(element);

                // Invalidate arrange so that repeater can arrange this element off-screen.
                m_owner.InvalidateArrange();
            }
        }
Ejemplo n.º 3
0
        void UpdateFocusedElement()
        {
            UIElement focusedElement = null;

            if (FocusManager.GetFocusedElement() is DependencyObject child)
            {
                var parent = CachedVisualTreeHelpers.GetParent(child);
                var owner  = (UIElement)m_owner;

                // Find out if the focused element belongs to one of our direct
                // children.
                while (parent != null)
                {
                    if (parent is ItemsRepeater repeater)
                    {
                        var element = child as UIElement;
                        if (repeater == owner && ItemsRepeater.GetVirtualizationInfo(element).IsRealized)
                        {
                            focusedElement = element;
                        }

                        break;
                    }

                    child  = parent;
                    parent = CachedVisualTreeHelpers.GetParent(child);
                }
            }

            // If the focused element has changed,
            // we need to unpin the old one and pin the new one.
            if (m_lastFocusedElement != focusedElement)
            {
                if (m_lastFocusedElement != null)
                {
                    UpdatePin(m_lastFocusedElement, false /* addPin */);
                }

                if (focusedElement != null)
                {
                    UpdatePin(focusedElement, true /* addPin */);
                }

                m_lastFocusedElement = focusedElement;
            }
        }
Ejemplo n.º 4
0
        // There are several cases handled here with respect to which element gets returned and when DataContext is modified.
        //
        // 1. If there is no ItemTemplate:
        //    1.1 If data is a UIElement . the data is returned
        //    1.2 If data is not a UIElement . a default DataTemplate is used to fetch element and DataContext is set to data**
        //
        // 2. If there is an ItemTemplate:
        //    2.1 If data is not a FrameworkElement . Element is fetched from ElementFactory and DataContext is set to the data**
        //    2.2 If data is a FrameworkElement:
        //        2.2.1 If Element returned by the ElementFactory is the same as the data . Element (a.k.a. data) is returned as is
        //        2.2.2 If Element returned by the ElementFactory is not the same as the data
        //                 . Element that is fetched from the ElementFactory is returned and
        //                    DataContext is set to the data's DataContext (if it exists), otherwise it is set to the data itself**
        //
        // **data context is set only if no x:Bind was used. ie. No data template component on the root.
        UIElement GetElementFromElementFactory(int index)
        {
            // The view generator is the provider of last resort.
            var data = m_owner.ItemsSourceView.GetAt(index);

            UIElement GetElement()
            {
                var elementFactory = m_owner.ItemTemplateShim;

                if (elementFactory == null)
                {
                    if (data is UIElement dataAsElement)
                    {
                        return(dataAsElement);
                    }
                    else
                    {
                        // If no ItemTemplate was provided, use a default
                        //var factory  = XamlReader.Load("<DataTemplate xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'><TextBlock Text='{Binding}'/></DataTemplate>") as DataTemplate;
                        var factory = new DataTemplate(() =>
                        {
                            var tb = new TextBlock();
                            tb.SetBinding(TextBlock.TextProperty, new Binding());
                            return(tb);
                        });
                        m_owner.ItemTemplate = factory;

                        elementFactory = m_owner.ItemTemplateShim;
                    }
                }

                if (m_ElementFactoryGetArgs == null)
                {
                    m_ElementFactoryGetArgs = new ElementFactoryGetArgs();
                }

                var args = m_ElementFactoryGetArgs;

                using var scopeGuard = Disposable.Create(() =>
                {
                    args.Data   = null;
                    args.Parent = null;
                });

                args.Data   = data;
                args.Parent = m_owner;
                args.Index  = index;

                return(elementFactory.GetElement(args));
            };

            var element = GetElement();

            var virtInfo = ItemsRepeater.TryGetVirtualizationInfo(element);

            if (virtInfo == null)
            {
                virtInfo = ItemsRepeater.CreateAndInitializeVirtualizationInfo(element);
                REPEATER_TRACE_PERF("ElementCreated");
            }
            else
            {
                // View obtained from ElementFactory already has a VirtualizationInfo attached to it
                // which means that the element has been recycled and not created from scratch.
                REPEATER_TRACE_PERF("ElementRecycled");
            }

            if (data != element)
            {
                // Prepare the element
                // If we are phasing, run phase 0 before setting DataContext. If phase 0 is not
                // run before setting DataContext, when setting DataContext all the phases will be
                // run in the OnDataContextChanged handler in code generated by the xaml compiler (code-gen).
                var extension = CachedVisualTreeHelpers.GetDataTemplateComponent(element);
                if (extension != null)
                {
                    // Clear out old data.
                    extension.Recycle();
                    int nextPhase = VirtualizationInfo.PhaseReachedEnd;
                    // Run Phase 0
                    extension.ProcessBindings(data, index, 0 /* currentPhase */, out nextPhase);

                    // Setup phasing information, so that Phaser can pick up any pending phases left.
                    // Update phase on virtInfo. Set data and templateComponent only if x:Phase was used.
                    virtInfo.UpdatePhasingInfo(nextPhase, nextPhase > 0 ? data : null, nextPhase > 0 ? extension : null);
                }
                else if (element is FrameworkElement elementAsFE)
                {
                    // Set data context only if no x:Bind was used. ie. No data template component on the root.
                    // If the passed in data is a UIElement and is different from the element returned by
                    // the template factory then we need to propagate the DataContext.
                    // Otherwise just set the DataContext on the element as the data.
                    var elementDataContext = data;
                    if (data is FrameworkElement dataAsElement)
                    {
                        var dataDataContext = dataAsElement.DataContext;
                        if (dataDataContext != null)
                        {
                            elementDataContext = dataDataContext;
                        }
                    }

                    elementAsFE.DataContext = elementDataContext;
                }
                else
                {
                    MUX_ASSERT(false, "Element returned by factory is not a FrameworkElement!");
                }
            }

            virtInfo.MoveOwnershipToLayoutFromElementFactory(
                index,
                /* uniqueId: */
                m_owner.ItemsSourceView.HasKeyIndexMapping ? m_owner.ItemsSourceView.KeyFromIndex(index) : null);

            // The view generator is the only provider that prepares the element.
            var repeater = m_owner;

#if IS_UNO  //TODO: Uno specific - remove when #4689 is fixed
            repeater.OnUnoBeforeElementPrepared(element, index);
#endif

            // Add the element to the children collection here before raising OnElementPrepared so
            // that handlers can walk up the tree in case they want to find their IndexPath in the
            // nested case.
            var children = repeater.Children;
            if (CachedVisualTreeHelpers.GetParent(element) != repeater)
            {
                children.Add(element);
            }

            repeater.AnimationManager.OnElementPrepared(element);

            repeater.OnElementPrepared(element, index);

            if (data != element)
            {
                m_phaser.PhaseElement(element, virtInfo);
            }

            // Update realized indices
            m_firstRealizedElementIndexHeldByLayout = Math.Min(m_firstRealizedElementIndexHeldByLayout, index);
            m_lastRealizedElementIndexHeldByLayout  = Math.Max(m_lastRealizedElementIndexHeldByLayout, index);

            return(element);
        }