// Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. // // Description: // AnnotationComponentManager // using System.Windows; using System.Windows.Annotations; using System.Windows.Documents; namespace MS.Internal.Annotations.Component { /// <summary> /// Instances of this class manage listen for events from the annotation service and create/remove/modify annotation components in response. /// Annotation components are created via indirection through an AnnotationComponentChooser which is set in a DP on the app tree. /// Annotation components are hosted, wrapped inside AnnotationAdorners, in an AdornerLayer respective to the annotated element. /// Every time an annotation service is instantiated an instance of this class is created. /// </summary> internal class AnnotationComponentManager : DependencyObject { #region Constructors /// <summary> /// Return an annotation component manager. If an annotation service is passed in, manager will /// receive notification from the service. Otherwise it will expect to be called directly. /// </summary> /// <param name="service">optional, annotation service the annotation component manager will register on</param> internal AnnotationComponentManager(AnnotationService service) : base() { // Only register if a service was passed in. If no service was passed in, we will not receive events. // This means a client will be calling us directly. service?.AttachedAnnotationChanged += new AttachedAnnotationChangedEventHandler(AttachedAnnotationUpdateEventHandler); } #endregion Constructors #region Internal Methods /// <summary> /// The given attached annotation was added by the annotation service /// Find annotation components for the given attached annotation, maintain /// mapping from attached annotation to annotation components, and add to the /// adorner layer if the annotation component is not already in a presentation context. /// </summary> /// <param name="attachedAnnotation">Attached annotation to add</param> /// <param name="reorder">If true - update components ZOrder after adding the component</param> internal void AddAttachedAnnotation(IAttachedAnnotation attachedAnnotation, bool reorder) { Debug.Assert(attachedAnnotation != null, "AttachedAnnotation should not be null"); IAnnotationComponent component = FindComponent(attachedAnnotation); if (component == null) return; AddComponent(attachedAnnotation, component, reorder); } /// <summary> /// The given attached annotation was removed by the annotation service. /// Find all annotation components and let them know. /// If an annotation component does not have any other attached annotations, remove it. /// Update the attachedAnnotations map. /// </summary> /// <param name="attachedAnnotation">Attached annotation to remove</param> /// <param name="reorder">If true - update components ZOrder after removing the component</param> internal void RemoveAttachedAnnotation(IAttachedAnnotation attachedAnnotation, bool reorder) { Debug.Assert(attachedAnnotation != null, "AttachedAnnotation should not be null"); if (!_attachedAnnotations.ContainsKey(attachedAnnotation)) { // note, this is not always a bug, since an annotation might have resolved, but no annotation component found // the tree traversal bug we have currently results in this failing even if annotation components were found, because // in certain cases annotationService.AttachedAnnotations returns wrong list. return; } IList<IAnnotationComponent> currentList = _attachedAnnotations[attachedAnnotation]; _attachedAnnotations.Remove(attachedAnnotation); // clean up the map foreach (IAnnotationComponent component in currentList) { component.RemoveAttachedAnnotation(attachedAnnotation); // let the annotation component know if (component.AttachedAnnotations.Count == 0) { // if it has no more attached annotations, remove it component.PresentationContext?.RemoveFromHost(component, reorder); } } } #endregion Internal Methods #region Private Methods /// <summary> /// Handle the notification coming from the service. Attached annotations can be added, removed, modified. /// Delegate to appropriate method /// </summary> /// <param name="sender">The sender of the event, an annotation service</param> /// <param name="e">The event arguments containing information on added/deleted/modified attached annotation.</param> private void AttachedAnnotationUpdateEventHandler(object sender, AttachedAnnotationChangedEventArgs e) { switch (e.Action) { case AttachedAnnotationAction.Added: this.AddAttachedAnnotation(e.AttachedAnnotation, true); break; case AttachedAnnotationAction.Deleted: this.RemoveAttachedAnnotation(e.AttachedAnnotation, true); break; case AttachedAnnotationAction.Loaded: this.AddAttachedAnnotation(e.AttachedAnnotation, false); break; case AttachedAnnotationAction.Unloaded: this.RemoveAttachedAnnotation(e.AttachedAnnotation, false); break; case AttachedAnnotationAction.AnchorModified: this.ModifyAttachedAnnotation(e.AttachedAnnotation, e.PreviousAttachedAnchor, e.PreviousAttachmentLevel); break; } } /// <summary> /// given an attachedAnnotation find the chooser attached at its parent /// and ask it to choose a component suitable to handle the attachedAnnotation /// </summary> /// <param name="attachedAnnotation">the attachedAnnotation we are to find a component for</param> /// <returns>an IAnnotationComponent that can handle the attachedAnnotation (or null)</returns> private IAnnotationComponent FindComponent(IAttachedAnnotation attachedAnnotation) { Debug.Assert(attachedAnnotation != null, "AttachedAnnotation should not be null"); UIElement annotatedElement = attachedAnnotation.Parent as UIElement; // casted from DependencyObject Debug.Assert(annotatedElement != null, "the annotatedElement should inherit from UIElement"); AnnotationComponentChooser chooser = AnnotationService.GetChooser(annotatedElement); // should we return a list instead? IAnnotationComponent component = chooser.ChooseAnnotationComponent(attachedAnnotation); return component; } /// <summary> /// Add an attached annotation to a component and add the component to the adorner layer /// if the annotation component is not already in a presentation context. /// </summary> /// <param name="attachedAnnotation">the attachedAnnotation we are to add to the component</param> /// <param name="component">the component we are to add to the adorner layer</param> /// <param name="reorder">if true - the z-order must be reevaluated</param> private void AddComponent(IAttachedAnnotation attachedAnnotation, IAnnotationComponent component, bool reorder) { UIElement annotatedElement = attachedAnnotation.Parent as UIElement; // casted from DependencyObject Debug.Assert(annotatedElement != null, "the annotatedElement should inherit from UIElement"); // if annotation component is already in presentation context, nothing else to do if (component.PresentationContext != null) return; // otherwise host in the appropriate adorner layer AdornerLayer layer = AdornerLayer.GetAdornerLayer(annotatedElement); // note, GetAdornerLayer requires UIElement if (layer == null) { if (PresentationSource.FromVisual(annotatedElement) == null) { // The annotated element is no longer part of the application tree. // This probably means we are out of sync - trying to add an annotation // for an element that has already gone away. Bug # 1580288 tracks // the need to figure this out. return; } throw new InvalidOperationException(SR.Format(SR.NoPresentationContextForGivenElement, annotatedElement)); } // add to the attachedAnnotations this.AddToAttachedAnnotations(attachedAnnotation, component); // let the annotation component know about the attached annotation // call add before adding to adorner layer so the component can be initialized component.AddAttachedAnnotation(attachedAnnotation); // this might cause recursion in modify if annotation component adds to annotation AdornerPresentationContext.HostComponent(layer, component, annotatedElement, reorder); } /// <summary> /// Service indicates attached annotation has changed. /// For now, take all annotation components maped from old attached annotation and map from new. /// Then iterate through annotation components to let them know. /// Note, this needs to change later. If modify is radical, existing component might not want it anymore, /// and new one might need to be found... /// </summary> /// <param name="attachedAnnotation">The modified attached annotation</param> /// <param name="previousAttachedAnchor">The previous attached anchor for the attached annotation</param> /// <param name="previousAttachmentLevel">The previous attachment level for the attached annotation</param> private void ModifyAttachedAnnotation(IAttachedAnnotation attachedAnnotation, object previousAttachedAnchor, AttachmentLevel previousAttachmentLevel) { Debug.Assert(attachedAnnotation != null, "attachedAnnotation should not be null"); Debug.Assert(previousAttachedAnchor != null, "previousAttachedAnchor should not be null"); // if there was no component found for this attached annotation // then we treat the modify case as an add if (!_attachedAnnotations.ContainsKey(attachedAnnotation)) { // this is not necessarily a bug, it can be that the old attached annotation does not have an // associated annotation component. this.AddAttachedAnnotation(attachedAnnotation, true); return; } // we have a previous component for this attached annotation // we find the chooser for the new attached annotation // and ask it to choose a component // 1- if it returned null then we just remove the attached annotation // 2- if it returned a different component, then we treat it as a remove/add // 3- if it returned the same component then we call ModifyAttachedAnnotation on the component IAnnotationComponent newComponent = FindComponent(attachedAnnotation); if (newComponent == null) { RemoveAttachedAnnotation(attachedAnnotation, true); } else { IList<IAnnotationComponent> currentList = _attachedAnnotations[attachedAnnotation]; //save the current list // if we found the new component in any of the list of components we already have for this // attached annotation if (currentList.Contains(newComponent)) { // ask the components to handle the anchor modification event foreach (IAnnotationComponent component in currentList) { component.ModifyAttachedAnnotation(attachedAnnotation, previousAttachedAnchor, previousAttachmentLevel); // let the annotation component know if (component.AttachedAnnotations.Count == 0) { // if component decides it can not handle it, remove it component.PresentationContext.RemoveFromHost(component, true); } } } else { // remove all components RemoveAttachedAnnotation(attachedAnnotation, true); // add the new component AddComponent(attachedAnnotation, newComponent, true); } } } /// <summary> /// Add to the map from attached annotations -> annotation components /// </summary> /// <param name="attachedAnnotation">The attached annotation to use as key</param> /// <param name="component">The component to add to list</param> private void AddToAttachedAnnotations(IAttachedAnnotation attachedAnnotation, IAnnotationComponent component) { Debug.Assert(attachedAnnotation != null, "attachedAnnotation should not be null"); Debug.Assert(component != null, "component should not be null"); IList<IAnnotationComponent> currentList; if (!_attachedAnnotations.TryGetValue(attachedAnnotation, out currentList)) { currentList = new List<IAnnotationComponent>(); _attachedAnnotations[attachedAnnotation] = currentList; } currentList.Add(component); } #endregion Private Methods #region Private Fields /// <summary> /// Map from attached annotation to list of annotation components. /// This map contains all attached anntotations the component manager currently knows. /// </summary> private Dictionary<IAttachedAnnotation, IList<IAnnotationComponent>> _attachedAnnotations = new Dictionary<IAttachedAnnotation, IList<IAnnotationComponent>>(); #endregion Private Fields } }