Navigation Pane
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This document describes the structure of a PDF Viewer’s navigation pane and explains how it can be customized.
This document contains the following sections.
Overview
The navigation pane is used to display thumbnails, bookmarks, and attachments in corresponding panels.
You can open (close) Page Thumbnails, Bookmarks or Attachments panel using the corresponding tab in the navigation pane.
Note
The Bookmarks tab appears only if a PDF document contains bookmarks.
To expand or collapse navigation panels, use the corresponding button (see the image above).
The Bookmarks panel represents items as a table of contents where you can perform actions (e.g., change the text size of nodes, hide the bookmarks panel after clicking on the bookmark item, etc.).
For more information on the Bookmarks panel, see the Bookmarks document.
The Attachments panel displays file attachments, and allows you to open and save an attachment to the disk.
To learn more about the Attachments panel, see the File Attachment document.
The Page Thumbnails panel displays thumbnails of the pages. The thumbnails allow you to navigate quickly between pages.
You can also print pages that correspond to the selected thumbnails.
To learn more about the Page Thumbnails panel, see the Thumbnails document.
Customization
The PDF Viewer provides properties to customize the navigation pane visibility and width. You can also programmatically select the navigation pane page.
Changing the navigation pane visibility
To change the navigation pane visibility for the PDF Viewer, use the PdfViewer.NavigationPaneVisibility (specifies the navigation pane’s current visibility state) and PdfViewer.NavigationPaneInitialVisibility (specifies the navigation pane visibility behavior after loading a new PDF document) properties. These properties can be set to one of the following values.
- Default - this option is used for the PdfViewer.NavigationPaneInitialVisibility property only
- Expanded - the pane is expanded
- Collapsed - the pane is collapsed
- Visible – the pane is visible
- Hidden – the pane is hidden
When the PdfViewer.NavigationPaneInitialVisibility property is set to PdfNavigationPaneVisibility.Default, it sets the PdfViewer.NavigationPaneVisibility property either to Visible if a PDF document contains bookmarks (the Bookmarks panel is shown in visible state), or to Collapsed if a PDF document does not have bookmarks and the Attachments panel is collapsed on the navigation pane.
You can customize the navigation pane behavior after the pane visibility is changed by handling the PdfViewer.NavigationPaneVisibilityChanged event.
Finally, you can change the visibility of Page Thumbnails, Bookmarks, and Attachments pages on the Navigation pane using the PdfViewer.NavigationPanePageVisibility property. For example, to show only the Attachments page on the Navigation pane, set the PdfViewer.NavigationPanePageVisibility property to PdfNavigationPanePageVisibility.Attachments.
Selecting the navigation pane page
You can programmatically select the navigation pane page.
To specify the Thumbnails, Bookmarks, or Attachments page that should be selected on the navigation pane after loading a new document, use the PdfViewer.NavigationPaneInitialSelectedPage property. This property returns one of four PdfNavigationPanePage enumeration values: Attachments, Bookmarks, Thumbnails, and Default. In Default mode, the Bookmarks page is opened if a document contains bookmarks. Otherwise, the Thumbnails page is shown on the navigation pane.
The PdfViewer.NavigationPaneInitialSelectedPage property automatically assigns its value to the PdfViewer.NavigationPaneSelectedPage property after a document is loaded to the PDF Viewer.
The PdfViewer.NavigationPaneSelectedPage property also returns one of the PdfNavigationPanePage enumeration values, except for Default. This property allows you to obtain the currently selected page that is opened on the navigation pane. Using this property, you can also select a current page programmatically on the navigation pane. When the Default value is set, the Bookmarks page is opened if a document contains bookmarks. Otherwise, the Thumbnails page is shown on the navigation pane.
Note
The NavigationPaneSelectedPage property does not select a page on the navigation pane if the selected page is hidden using the PPdfViewer.NavigationPanePageVisibility property or the Bookmarks page is specified for a document that does not contain bookmarks.
When a page is changed on the navigation pane, the PdfViewer.NavigationPaneSelectedPageChanged event is raised. In this event, you can obtain the previously and currently selected page using the PdfNavigationPaneSelectedPageChangedEventArgs.PreviousSelectedPage and PdfNavigationPaneSelectedPageChangedEventArgs.SelectedPage properties.
Changing the navigation pane width
To change the width of a navigation pane, use the PdfViewer.NavigationPaneWidth property. The default value of the property is 0 (the navigation pane size is measured in pixels). If the default value is used, the navigation pane has 1/5 of the current viewer’s size.
The minimum pane width can be accessed using the PdfViewer.NavigationPaneMinWidth property.