AnnotationAdorner.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / MS / Internal / Annotations / Component / AnnotationAdorner.cs / 1305600 / AnnotationAdorner.cs
                        

                        
                            //---------------------------------------------------------------------------- 
// 
//    Copyright(C) Microsoft Corporation.  All rights reserved.
// 
// 
// Description:
//      AnnotationAdorner wraps an IAnnotationComponent.  Its the bridge 
//      between the component and the adorner layer. 
//
// History: 
//  04/01/2004: axelk:   Created AnnotationAdorner.cs
//  10/20/2004: rruiz:   Moved class to MS.Internal.
//
// Copyright(C) 2002 by Microsoft Corporation.  All rights reserved. 
//---------------------------------------------------------------------------
using System; 
using System.Collections.Generic; 
using System.Diagnostics;
using System.Windows; 
using System.Windows.Documents;
using System.Windows.Media;

namespace MS.Internal.Annotations.Component 
{
    ///  
    /// An adorner which wraps one IAnnotationComponent.  The wrapped component must be at least a UIElement. 
    /// Adorners are UIElements.
    /// Note:-This class is sealed because it calls OnVisualChildrenChanged virtual in the 
    ///           constructor and it does not override it, but derived classes could.
    /// 
    internal sealed class AnnotationAdorner : Adorner
    { 

        #region Constructors 
 
        /// 
        /// Return an initialized annotation adorner 
        /// 
        /// The annotation component to wrap in the annotation adorner
        /// element being annotated
        public AnnotationAdorner(IAnnotationComponent component, UIElement annotatedElement): base(annotatedElement) 
        {
            //The summary on top of the file says:- 
            //The wrapped component must be at least a UIElement 
            if(component is UIElement)
            { 
                _annotationComponent = component;
                // wrapped annotation component is added as visual child
                this.AddVisualChild((UIElement)_annotationComponent);
            } 
            else
            { 
                throw new ArgumentException(SR.Get(SRID.AnnotationAdorner_NotUIElement), "component"); 
            }
        } 

        #endregion Constructors

        #region Public Methods 

        ///  
        /// Forwarded to the annotation component to get desired transform relative to the annotated element 
        /// 
        /// Transform to adorned element 
        /// Transform to annotation component 
        public override GeneralTransform GetDesiredTransform(GeneralTransform transform)
        {
            //if the component is not visual we do not need this 
            if (!(_annotationComponent is UIElement))
                return null; 
 
            // Give the superclass a chance to modify the transform
            transform = base.GetDesiredTransform(transform); 

            GeneralTransform compTransform = _annotationComponent.GetDesiredTransform(transform);

            //ToDo. if the annotated element is null this component must be unloaded. 
            //Temporary return null until the PageViewer Load/Unload bug is fixed
            //Convert it to an exception after that. 
            if (_annotationComponent.AnnotatedElement == null) 
                return null;
 
            if (compTransform == null)
            {
                // We need to store the element we are registering on.  It may not
                // be available from the annotation component later. 
                _annotatedElement = _annotationComponent.AnnotatedElement;
 
                // Wait for valid text view 
                _annotatedElement.LayoutUpdated += OnLayoutUpdated;
                return transform; 
            }

            return compTransform;
        } 

        #endregion Public Methods 
 
        #region Protected Methods
 
        /// 
        ///   Derived class must implement to support Visual children. The method must return
        ///    the child at the specified index. Index must be between 0 and GetVisualChildrenCount-1.
        /// 
        ///    By default a Visual does not have any children.
        /// 
        ///  Remark: 
        ///       During this virtual call it is not valid to modify the Visual tree.
        ///  
        protected override Visual GetVisualChild(int index)
        {
            if(index != 0 || _annotationComponent == null)
            { 
                throw new ArgumentOutOfRangeException("index", index, SR.Get(SRID.Visual_ArgumentOutOfRange));
            } 
 
            return (UIElement)_annotationComponent;
        } 

        /// 
        ///  Derived classes override this property to enable the Visual code to enumerate
        ///  the Visual children. Derived classes need to return the number of children 
        ///  from this method.
        /// 
        ///    By default a Visual does not have any children. 
        ///
        ///  Remark: During this virtual method the Visual tree must not be modified. 
        /// 
        protected override int VisualChildrenCount
        {
            get { return _annotationComponent != null ? 1 : 0; } 
        }
 
        ///  
        /// Measurement override. Delegated to children.
        ///  
        /// Available size for the component
        /// Return the size enclosing all children
        protected override Size MeasureOverride(Size availableSize)
        { 
            Size childConstraint = new Size(Double.PositiveInfinity, Double.PositiveInfinity);
 
            Invariant.Assert(_annotationComponent != null, "AnnotationAdorner should only have one child - the annotation component."); 

            ((UIElement)_annotationComponent).Measure(childConstraint); 

            return new Size(0,0);
        }
 
        /// 
        /// Override for  
        ///  
        /// The location reserved for this element by the parent
        protected override Size ArrangeOverride(Size finalSize) 
        {
            Invariant.Assert(_annotationComponent != null, "AnnotationAdorner should only have one child - the annotation component.");

            ((UIElement)_annotationComponent).Arrange(new Rect(((UIElement)_annotationComponent).DesiredSize)); 

            return finalSize; 
        } 

        #endregion ProtectedMethods 

        #region Internal Methods

        ///  
        /// Remove all visual children of this AnnotationAdorner.
        /// Called by AdornerPresentationContext when an annotation adorner is removed from the adorner layer hosting it. 
        ///  
        internal void RemoveChildren()
        { 
            this.RemoveVisualChild((UIElement)_annotationComponent);
            _annotationComponent = null;
        }
 
        /// 
        /// Call this if the visual of the annotation changes. 
        /// This ill invalidate the AnnotationAdorner and the AdornerLayer which 
        /// will invoke remeasuring of the annotation visual.
        ///  
        internal void InvalidateTransform()
        {
            AdornerLayer adornerLayer = (AdornerLayer)VisualTreeHelper.GetParent(this);
 
            InvalidateMeasure();
            adornerLayer.InvalidateVisual(); 
        } 

        #endregion Internal Methods 

        #region Internal Properties

        ///  
        ///  Return the annotation component that is being wrapped.  AdornerPresentationContext needs this.
        ///  
        /// Wrapped annotation component 
        internal IAnnotationComponent AnnotationComponent
        { 
            get { return _annotationComponent; }
        }

        #endregion Internal Properties 

        #region Private Methods 
 
        /// 
        /// LayoutUpdate event handler 
        /// 
        /// event sender (not used)
        /// event arguments (not used)
        private void OnLayoutUpdated(object sender, EventArgs args) 
        {
            // Unregister for the event 
            _annotatedElement.LayoutUpdated -= OnLayoutUpdated; 
            _annotatedElement = null;
 
            // If there are still annotations to display, update the UI
            if (_annotationComponent.AttachedAnnotations.Count > 0)
            {
                _annotationComponent.PresentationContext.Host.InvalidateMeasure(); 
                this.InvalidateMeasure();
            } 
        } 

        #endregion Private Methods 

        #region Private Fields

        ///  
        /// The wrapped annotation component
        ///  
        private IAnnotationComponent _annotationComponent; 

        ///  
        /// Used to unregister for the LayoutUpdated event - necessary because in the
        /// the component may have its annotated element cleared before we can unregister.
        /// 
        private UIElement _annotatedElement; 

        #endregion Private Fields 
    } 
}
 




// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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