/// <summary>
/// Determine if the specified type is an DataServiceCollection.
/// </summary>
/// <remarks>
/// If there a generic class in the inheritance hierarchy of the type, that has a single
/// entity type paramenter T, and is assignable to DataServiceCollection(Of T), then
/// the type is an DataServiceCollection.
/// </remarks>
/// <param name="collectionType">An object type specifier.</param>
/// <param name="model">The client model.</param>
/// <returns>true if the type is an DataServiceCollection; otherwise false.</returns>
internal static bool IsDataServiceCollection(Type collectionType, ClientEdmModel model)
{
Debug.Assert(collectionType != null, "Argument 'collectionType' cannot be null.");
metadataCacheLock.EnterReadLock();
try
{
object resultAsObject;
if (knownObservableCollectionTypes.TryGetValue(collectionType, out resultAsObject))
{
return(resultAsObject == TrueObject);
}
}
finally
{
metadataCacheLock.ExitReadLock();
}
Type type = collectionType;
bool result = false;
while (type != null)
{
if (type.IsGenericType())
{
// Is there a generic class in the inheritance hierarchy, that has a single
// entity type paramenter T, and is assignable to DataServiceCollection<T>
Type[] parms = type.GetGenericArguments();
if (parms != null && parms.Length == 1 && ClientTypeUtil.TypeOrElementTypeIsEntity(parms[0]))
{
// if ObservableCollection is not available dataServiceCollection will be null
Type dataServiceCollection = WebUtil.GetDataServiceCollectionOfT(parms);
if (dataServiceCollection != null && dataServiceCollection.IsAssignableFrom(type))
{
result = true;
break;
}
}
}
type = type.GetBaseType();
}
metadataCacheLock.EnterWriteLock();
try
{
if (!knownObservableCollectionTypes.ContainsKey(collectionType))
{
knownObservableCollectionTypes[collectionType] = result ? TrueObject : FalseObject;
}
}
finally
{
metadataCacheLock.ExitWriteLock();
}
return(result);
}
/// <summary>
/// Checks whether the specified expression creates a collection.
/// </summary>
/// <param name="e">Expression to check.</param>
/// <returns>true if given expression is collection producing.</returns>
internal static bool IsCollectionProducingExpression(Expression e)
{
if (TypeSystem.FindIEnumerable(e.Type) != null)
{
Type elementType = TypeSystem.GetElementType(e.Type);
Debug.Assert(elementType != null, "elementType == null");
Type dscType = WebUtil.GetDataServiceCollectionOfT(elementType);
if (typeof(List <>).MakeGenericType(elementType).IsAssignableFrom(e.Type) ||
(dscType != null && dscType.IsAssignableFrom(e.Type)))
{
return(true);
}
}
return(false);
}