private ViewRecord GetViewRecord(object source)
{
// Order of precendence in acquiring the View:
// 1) If the CollectionView for this collection has been cached, then
// return the cached instance.
// 2) If the collection is an ICollectionViewFactory use ICVF.CreateView()
// from the collection
// 3) If the collection is an IList return a new ListCollectionView
// 4) If the collection is an IEnumerable, return a new EnumerableCollectionView
// 5) return null
// if the view already exists, just return it
ViewRecord viewRecord = GetExistingViewRecord(source);
if (viewRecord != null)
{
return(viewRecord);
}
ICollectionView icv = null;
ICollectionViewFactory icvf = source as ICollectionViewFactory;
if (icvf != null)
{
// collection is a view factory - call its factory method
icv = icvf.CreateView();
}
else
{
// collection is not a factory - create an appropriate view
IList il = source as IList;
if (il != null)
{
icv = new ListCollectionView(il);
}
else
{
// collection is not IList, wrap it
IEnumerable ie = source as IEnumerable;
if (ie != null)
{
icv = new EnumerableCollectionView(ie);
}
}
}
// if we got a view, add it to the tables
if (icv != null)
{
viewRecord = new ViewRecord(icv);
this.CachedViews[source] = viewRecord;
}
return(viewRecord);
}
/// <summary>
/// Creates a collection view around the DataGrid's source. ICollectionViewFactory is
/// used if the source implements it. Otherwise a PagedCollectionView is returned.
/// </summary>
/// <param name="source">Enumerable source for which to create a view</param>
/// <returns>ICollectionView view over the provided source</returns>
#else
/// <summary>
/// Creates a collection view around the DataGrid's source. ICollectionViewFactory is
/// used if the source implements it.
/// </summary>
/// <param name="source">Enumerable source for which to create a view</param>
/// <returns>ICollectionView view over the provided source</returns>
#endif
internal static ICollectionView CreateView(IEnumerable source)
{
Debug.Assert(source != null, "source unexpectedly null");
Debug.Assert(!(source is ICollectionView), "source is an ICollectionView");
ICollectionView collectionView = null;
ICollectionViewFactory collectionViewFactory = source as ICollectionViewFactory;
if (collectionViewFactory != null)
{
// If the source is a collection view factory, give it a chance to produce a custom collection view.
collectionView = collectionViewFactory.CreateView();
// Intentionally not catching potential exception thrown by ICollectionViewFactory.CreateView().
}
#if FEATURE_PAGEDCOLLECTIONVIEW
if (collectionView == null)
{
collectionView = new PagedCollectionView(source);
}
#endif
if (collectionView == null)
{
IList sourceAsList = source as IList;
if (sourceAsList != null)
{
collectionView = new ListCollectionView(sourceAsList);
}
else
{
collectionView = new EnumerableCollectionView(source);
}
}
return(collectionView);
}
