/// <summary>Enumerates casting each element to a type.</summary>
/// <typeparam name="T">Element type to enumerate over.</typeparam>
/// <param name="source">Element source.</param>
/// <returns>
/// An IEnumerable<T> that iterates over the specified <paramref name="source"/>.
/// </returns>
/// <remarks>
/// This method should be unnecessary with .NET 4.0 covariance support.
/// </remarks>
internal static IEnumerable <T> EnumerateAsElementType <T>(IEnumerable source)
{
return(ODataEntityMaterializer.EnumerateAsElementType <T>(source));
}
/// <summary>
/// Applies the values of the <paramref name="items"/> enumeration to the
/// <paramref name="property"/> of the specified <paramref name="entry"/>.
/// </summary>
/// <param name="entry">Entry with collection to be modified.</param>
/// <param name="property">Collection property on the entry.</param>
/// <param name="items">Values to apply onto the collection.</param>
/// <param name="nextLink">Next link for collection continuation.</param>
/// <param name="continuationPlan">Projection plan for collection continuation.</param>
/// <param name="isContinuation">Whether this is a continuation request.</param>
internal void ApplyItemsToCollection(
MaterializerEntry entry,
ClientPropertyAnnotation property,
IEnumerable items,
Uri nextLink,
ProjectionPlan continuationPlan,
bool isContinuation)
{
Debug.Assert(entry.Entry != null || entry.ForLoadProperty, "ODataResource should be non-null except for LoadProperty");
Debug.Assert(property != null, "property != null");
Debug.Assert(items != null, "items != null");
IEnumerable <object> itemsEnumerable = ODataEntityMaterializer.EnumerateAsElementType <object>(items);
// Populate the collection property with items collection.
object collection = this.PopulateCollectionProperty(entry, property, itemsEnumerable, nextLink, continuationPlan);
// Get collection of all non-linked elements in collection and remove them except for the ones that were obtained from the response.
if (this.EntityTrackingAdapter.MergeOption == MergeOption.OverwriteChanges ||
this.EntityTrackingAdapter.MergeOption == MergeOption.PreserveChanges)
{
var linkedItemsInCollection =
this.EntityTrackingAdapter
.EntityTracker
.GetLinks(entry.ResolvedObject, property.PropertyName)
.Select(l => new { l.Target, l.IsModified });
if (collection != null && !property.IsDictionary)
{
var nonLinkedNonReceivedItemsInCollection = ODataEntityMaterializer.EnumerateAsElementType <object>((IEnumerable)collection)
.Except(linkedItemsInCollection.Select(i => i.Target))
.Except(itemsEnumerable).ToArray();
// Since no link exists, we just remove the item from the collection
foreach (var item in nonLinkedNonReceivedItemsInCollection)
{
property.RemoveValue(collection, item);
}
}
// When the first time a property or collection is being loaded, we remove all items other than the ones that we receive.
if (!isContinuation)
{
IEnumerable <object> itemsToRemove;
if (this.EntityTrackingAdapter.MergeOption == MergeOption.OverwriteChanges)
{
itemsToRemove = linkedItemsInCollection.Select(i => i.Target);
}
else
{
Debug.Assert(
this.EntityTrackingAdapter.MergeOption == MergeOption.PreserveChanges,
"this.EntityTrackingAdapter.MergeOption == MergeOption.PreserveChanges");
itemsToRemove = linkedItemsInCollection
.Where(i => !i.IsModified)
.Select(i => i.Target);
}
itemsToRemove = itemsToRemove.Except(itemsEnumerable);
foreach (var item in itemsToRemove)
{
if (collection != null)
{
property.RemoveValue(collection, item);
}
this.EntityTrackingAdapter.MaterializationLog.RemovedLink(entry, property.PropertyName, item);
}
}
}
}