Tuesday, July 24, 2012

Cocoon Framework v0.9.2 Released

As I discussed in my previous post on NuGet support in the Cocoon framework, I will be distributing major updates within the framework as new releases. Today I am pleased to say that version 0.9.2 is available from both the Cocoon CodePlex site and downloadable directly from NuGet.

New Features in This Release

This release has mainly focussed upon updates to the Cocoon data framework. In particular,

  • Significant improvements in how the data framework handles caching of list items.
  • Infrastructure added to support change notifications for data lists.
  • The ‘PagedDataListSource’ class now includes a ‘PageCacheSize’ property that allows you to specify the maximum number of pages to hold in memory at any one time (by default all pages are stored).
  • Introduction of an ‘IncrementalLoadingDataList’ class. This supports the Windows 8 Metro ISupportIncrementalLoading interface. This allows a data bound UI to download a small subset of a large list of items, with further items being retrieved and added when the user scrolls to the end of the list.
  • A Refresh() method has been added to SimpleDataListSource and PagedDataListSource. This allows you to clear the internal cache and re-fetch any data that may have changed. Any attached data lists will automatically update to reflect the changes.

Some improvements to the navigation framework include,

  • Updated to support MEF version 1.0.11-rc.
  • Changes to the ‘CocoonBootstrapper’ to help with a convention based approach to exporting pages and view models (I will write a blog post on this in the future).
  • The navigation manager now exposes a ‘CurrentPage’ property so that you can programmatically determine the currently displayed page and associated information.
  • Pages and view-models can now be named by specifying a type as an alternative to a string page name.
  • A MEF sharing boundary (named “page”) has been placed around each page and view model pair (see here for more information on MEF sharing boundaries).
  • Some common MVVM base classes have been included. Whilst you are not restricted to using these to take advantage of the Cocoon framework they provide basic functionality that is common to many applications. These classes include,
    • DelegateCommand and DelegateCommand<T> – implementations of the ICommand interface that allow you to bind UI interactions to methods on your view models.
    • NotifyPropertyChangedBase – provides a simple base class for view models that supports property change notification.
  • A number of other bug fixes.

Breaking Changes

Unfortunately there are a small number of breaking changes in this release. For most developers however the changes should be minimal.

  • ‘SpecialPageNames.HomePage’ has been renamed ‘SpecialPageNames.Home’.
  • The contract for IDataListSource has changed. Note that this should only affect developers who are writing custom IDataListSource implementations. If you are using SimpleDataListSource or PagedDataListSource then existing code should not be affected. In particular the changes are,
    • Addition of an IndexOf(…) method to the IDataListSource interface.
    • The data list source implementations are now fully responsible for caching of data.
  • The ‘InternalList’ property of ‘DataListSourceBase’ has been removed (derived classes should create their own internal cache) and the corresponding property in ‘SimpleDataListSource’ and ‘PagedDataListSource’ has been made private.
  • VirtualizingVector<T> is now marked as Obsolete – it is recommended that you use the data list support or the new VirtualizingVectorBase<T>.

Getting the Latest Version of Cocoon

To get the latest release of the Cocoon framework the best place to start is using the NuGet package manager to download the “Cocoon Framework” package (see here for more information). If you are already using Cocoon via NuGet then you should be able to update your solution to the latest version directly through the NuGet package manager.

Alternatively the source code is available via the Cocoon CodePlex downloads page. As always the latest interim code drops are also available from CodePlex under the source code tab.

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