ContentHostHelper.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / MS / Internal / documents / ContentHostHelper.cs / 1 / ContentHostHelper.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
//
// File: ContentHostHelper.cs 
//
// Description: The ContentHostHelper class contains static methods that are 
//              useful for performing common tasks with IContentHost. 
//
//--------------------------------------------------------------------------- 

using System;                               // Object
using System.Collections.Generic;           // List
using System.Windows;                       // IContentHost 
using System.Windows.Controls;              // TextBlock
using System.Windows.Controls.Primitives;   // DocumentPageView 
using System.Windows.Documents;             // FlowDocument 
using System.Windows.Media;                 // Visual
using MS.Internal.PtsHost;                  // FlowDocumentPage 

namespace MS.Internal.Documents
{
    ///  
    /// Static helper functions for dealing with IContentHost.
    ///  
    internal static class ContentHostHelper 
    {
        //------------------------------------------------------------------- 
        //
        //  Internal Methods
        //
        //------------------------------------------------------------------- 

        #region Internal Methods 
 
        /// 
        /// Given a ContentElement searches for associated IContentHost, if one exists. 
        /// 
        /// Content element
        /// Associated IContentHost with ContentElement.
        internal static IContentHost FindContentHost(ContentElement contentElement) 
        {
            IContentHost ich = null; 
            DependencyObject parent; 
            TextContainer textContainer;
 
            if (contentElement == null) { return null; }

            // If the ContentElement is a TextElement, retrieve IContentHost form the owner
            // of TextContainer. 
            if (contentElement is TextElement)
            { 
                textContainer = ((TextElement)contentElement).TextContainer; 
                parent = textContainer.Parent;
                if (parent is IContentHost) // TextBlock 
                {
                    ich = (IContentHost)parent;
                }
                else if (parent is FlowDocument) // Viewers 
                {
                    ich = GetICHFromFlowDocument((TextElement)contentElement, (FlowDocument)parent); 
                } 
                else if (textContainer.TextView != null && textContainer.TextView.RenderScope is IContentHost)
                { 
                    // TextBlock hosted in ControlTemplate
                    ich = (IContentHost)textContainer.TextView.RenderScope;
                }
            } 
            // else; cannot retrive IContentHost
 
            return ich; 
        }
 
        #endregion Internal Methods

        //--------------------------------------------------------------------
        // 
        //  Private Methods
        // 
        //------------------------------------------------------------------- 

        #region Private Methods 

        /// 
        /// Given a ContentElement within FlowDocument searches for associated IContentHost.
        ///  
        /// Content element
        /// FlowDocument hosting ContentElement. 
        /// Associated IContentHost with ContentElement. 
        private static IContentHost GetICHFromFlowDocument(TextElement contentElement, FlowDocument flowDocument)
        { 
            IContentHost ich = null;
            List pageViews;
            ITextView textView = flowDocument.StructuralCache.TextContainer.TextView;
 
            if (textView != null)
            { 
                // If FlowDocument is hosted by FlowDocumentScrollViewer, the RenderScope 
                // is FlowDocumentView object which hosts PageVisual representing the content.
                // This PageVisual is also IContentHost for the entire content of DocumentPage. 
                if (textView.RenderScope is FlowDocumentView) // FlowDocumentScrollViewer
                {
                    if (VisualTreeHelper.GetChildrenCount(textView.RenderScope) > 0)
                    { 
                        ich = VisualTreeHelper.GetChild(textView.RenderScope, 0) as IContentHost;
                    } 
                } 
                // Our best guess is that FlowDocument is hosted by DocumentViewerBase.
                // In this case search the style for all DocumentPageViews. 
                // Having collection of DocumentPageViews, find for the one which hosts TextElement.
                else if (textView.RenderScope is FrameworkElement)
                {
                    pageViews = new List(); 
                    FindDocumentPageViews(textView.RenderScope, pageViews);
                    for (int i = 0; i < pageViews.Count; i++) 
                    { 
                        if (pageViews[i].DocumentPage is FlowDocumentPage)
                        { 
                            textView = (ITextView)((IServiceProvider)pageViews[i].DocumentPage).GetService(typeof(ITextView));
                            if (textView != null && textView.IsValid)
                            {
                                // Check if the page contains ContentElement. Check Start and End 
                                // position, which will give desired results in most of the cases.
                                // Having hyperlink spanning more than 2 pages is not very common, 
                                // and this code will not work with it correctly. 
                                if (textView.Contains(contentElement.ContentStart) ||
                                    textView.Contains(contentElement.ContentEnd)) 
                                {
                                    ich = pageViews[i].DocumentPage.Visual as IContentHost;
                                }
                            } 
                        }
                    } 
                } 
            }
 
            return ich;
        }

        ///  
        /// Does deep Visual tree walk to retrieve all DocumentPageViews.
        /// It stops recursing down into visual tree in following situations: 
        /// a) Visual is UIElement and it is not part of Contol Template, 
        /// b) Visual is DocumentPageView.
        ///  
        /// FrameworkElement that is part of Control Template.
        /// Collection of DocumentPageViews; found elements are appended here.
        /// Whether collection of DocumentPageViews has been updated.
        private static void FindDocumentPageViews(Visual root, List pageViews) 
        {
            Invariant.Assert(root != null); 
            Invariant.Assert(pageViews != null); 

            if (root is DocumentPageView) 
            {
                pageViews.Add((DocumentPageView)root);
            }
            else 
            {
                FrameworkElement fe; 
                // Do deep tree walk to retrieve all DocumentPageViews. 
                // It stops recursing down into visual tree in following situations:
                // a) Visual is UIElement and it is not part of Contol Template, 
                // b) Visual is DocumentPageView.
                // Add to collection any DocumentPageViews found in the Control Template.
                int count = root.InternalVisualChildrenCount;
                for (int i = 0; i < count; i++) 
                {
                    Visual child = root.InternalGetVisualChild(i); 
                    fe = child as FrameworkElement; 
                    if (fe != null)
                    { 
                        if (fe.TemplatedParent != null)
                        {
                            if (fe is DocumentPageView)
                            { 
                                pageViews.Add(fe as DocumentPageView);
                            } 
                            else 
                            {
                                FindDocumentPageViews(fe, pageViews); 
                            }
                        }
                    }
                    else 
                    {
                        FindDocumentPageViews(child, pageViews); 
                    } 
                }
            } 
        }

        #endregion Private Methods
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ContentHostHelper.cs source code in C# .NET

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