This should be one of the ugliest extensions ever (in terms of code and visual effects), but it “makes the paragraph interchangeable” and text can still be selected.
public static class ParagraphExtensions { private static Dictionary<Paragraph, InlineUIContainer> _collapseButtonDictionary; private static Dictionary<Paragraph, List<Inline>> _paragraphInlineStorage; public static readonly DependencyProperty IsCollapsibleProperty = DependencyProperty.RegisterAttached("IsCollapsible", typeof(bool), typeof(Paragraph), new UIPropertyMetadata(false, IsCollapsibleChanged)); public static bool GetIsCollapsible(DependencyObject obj) { return (bool)obj.GetValue(IsCollapsibleProperty); } public static void SetIsCollapsible(DependencyObject obj, bool value) { obj.SetValue(IsCollapsibleProperty, value); } private static void IsCollapsibleChanged(object sender, DependencyPropertyChangedEventArgs e) { if (_collapseButtonDictionary == null) _collapseButtonDictionary = new Dictionary<Paragraph, InlineUIContainer>(); if (_paragraphInlineStorage == null) _paragraphInlineStorage = new Dictionary<Paragraph, List<Inline>>(); Paragraph p = sender as Paragraph; if ((bool)e.NewValue) { InlineUIContainer container; if (_collapseButtonDictionary.ContainsKey(p)) { container = _collapseButtonDictionary[p]; } else { ToggleButton button = new ToggleButton() { Tag = p, Content = "Hide" }; container = new InlineUIContainer() { Child = button }; _collapseButtonDictionary.Add(p, container); button.Click += new RoutedEventHandler(CollapseButton_Click); } if (p.Inlines.Count > 0) { p.Inlines.InsertBefore(p.Inlines.First(), container); } else { p.Inlines.Add(container); } } else { if (_collapseButtonDictionary.ContainsKey(p)) { var container = _collapseButtonDictionary[p]; var tb = container.Child as ToggleButton; if ((bool)tb.IsChecked) SetCollapsedState(false, p); p.Inlines.Remove(container); _collapseButtonDictionary.Remove(p); } } } private static void CollapseButton_Click(object sender, RoutedEventArgs e) { ToggleButton button = sender as ToggleButton; var p = button.Tag as Paragraph; SetCollapsedState((bool)button.IsChecked, p); } private static void SetCollapsedState(bool isCollapsed, Paragraph p) { InlineUIContainer buttonContainer = _collapseButtonDictionary[p]; List<Inline> disabledInlines; if (_paragraphInlineStorage.ContainsKey(p)) { disabledInlines = _paragraphInlineStorage[p]; } else { disabledInlines = new List<Inline>(); _paragraphInlineStorage.Add(p, disabledInlines); } if (isCollapsed) { foreach (var item in p.Inlines) { disabledInlines.Add(item); } p.Inlines.Clear(); p.Inlines.Add(buttonContainer); } else { p.Inlines.Clear(); foreach (var item in disabledInlines) { p.Inlines.Add(item); } disabledInlines.Clear(); } } }
<Paragraph local:ParagraphExtensions.IsCollapsible="True">Lorem Ipsum</Paragraph>
Clearly, creating a paragraph is probably not the best approach, I think that such functionality is what the document on the panel / cover should take care of.