Opening Existing Screens

Previously created Canvas screens and objects can be opened from the Backstage view or via the command line.

Note:

In Canvas, when opening a screen created in a pre-v9.6 version of Canvas that contains script, the screen will be converted to an updated script format when saved. In Canvas, a Script Change Pending message will warn you of the pending change. Older screens opened in Canvas View or Canvas View Lite will be converted on the fly, but not saved. See Script Format Changes in v9.5 and Later for more information.

Opening Screens from the Backstage View

  1. On the Canvas toolbar, click File or Open an existing screen (Open an existing screen (Ctrl+O)) to access the Backstage view to open existing Canvas files.
  1. In the Backstage view, click Open and do one of the following, depending on where your screen files are located:
    1. Recent files If your screen has been opened recently it will be listed in the recent files list. Click Recent to view the list of recently opened and pinned screens. See Opening Recent Screens for more information.
    2. Folder open If your screen files are stored in a local or network file system location rather than in your CygNet folder, click Browse to access an Open dialog box and navigate directly to the location of the selected screen file, and then double-click to open the screen.
    1. Folder in BSS If your screen files are stored in your CygNet folder, click to select a CygNet APPS or BSS:
      1. Folder Click to select a folder
      1. Screen Click to open the selected screen file in the Canvas screen window

Opening Files via the Windows Explorer

Any Canvas file can be opened from Windows Explorer by right-clicking a file name and selecting Open with > Canvas or Open with > Canvas.View.

Opening Files via the Command Line

Canvas supports a command-line option to open a specific screen from either a local or network Windows file-system folder or a CygNet APPS or BSS folder. See Starting Canvas from a Command Line for more information.

File Caching

Canvas, Canvas.View, and Canvas.View.Lite utilize a file cache to efficiently manage performance when opening individual screens and objects. This also applies to screens and objects used in Nested Views, the Object Container, and other controls. All requests for screens or objects are made to the file cache. If the cache contains the necessary screen, it will be returned. If the requested file is not in the cache, it is retrieved from either disk or the BSS, loaded into the file cache, and then returned to the caller. There is one exception to this:

Within Canvas, file open actions from the toolbar/Open menu will bypass the file cache and always open the file from either disk or the BSS. If a Canvas.View or Canvas.View.Lite client has already opened a screen and it then is modified by a Canvas user, the Canvas.View and Canvas.View.Lite client won’t retrieve the new screen until the client application is closed and reopened.

Additionally, when opening a screen from the toolbar/Open menu Canvas will load the file directly from the source, ignoring the screen cache, however if that screen contains any nested views or objects, those will still use the screen cache. Only the selected file is considered when ignoring the cache. Any related files that get opened in connection to the selected file are still pulled from the cache, if available.