public static IEnumerable <T> MakeProxy <T>(this IEnumerable <T> enumerable, CollectionProxyKind kind)
{
Contract.Requires(enumerable != null);
Contract.Ensures(Contract.Result <IEnumerable <T> >() != null);
return(MakeProxy(enumerable, kind, null));
}
public static IEnumerable MakeProxy(this IEnumerable enumerable,
CollectionProxyKind kind, bool?readOnly)
{
Contract.Requires(enumerable != null);
Contract.Ensures(Contract.Result <IEnumerable>() != null);
switch (kind)
{
case CollectionProxyKind.Enumerable:
return(new EnumerableProxy(enumerable));
case CollectionProxyKind.Collection:
if (true == readOnly)
{
var message = "Cannot make a read-only proxy of an IEnumerable.";
throw new InvalidOperationException(message);
}
if (!(enumerable is ICollection))
{
throw new ArgumentException("enumerable is not an ICollection.");
}
return(new CollectionProxy((ICollection)enumerable));
case CollectionProxyKind.List:
if (true == readOnly)
{
var message = "Cannot make a read-only proxy of an IEnumerable.";
throw new InvalidOperationException(message);
}
if (!(enumerable is IList))
{
throw new ArgumentException("enumerable is not an ICollection.");
}
return(new ListProxy((IList)enumerable));
default:
throw new ArgumentOutOfRangeException("kind");
}
}
public static IEnumerable <T> MakeProxy <T>(this IEnumerable <T> enumerable,
CollectionProxyKind kind, bool?readOnly)
{
Contract.Requires(enumerable != null);
Contract.Ensures(Contract.Result <IEnumerable <T> >() != null);
switch (kind)
{
case CollectionProxyKind.Enumerable:
return(new EnumerableProxy <T>(enumerable));
case CollectionProxyKind.Collection:
// If not explicit readonly
if (true != readOnly)
{
// Try to create mutable collection proxy
if (enumerable is ICollection <T> )
{
return(new CollectionProxy <T>((ICollection <T>)enumerable));
}
// Handle error if explicit mutable
if (false == readOnly)
{
throw new ArgumentException(
"Cannot create mutable proxy: enumerable is not ICollection<T>."
);
}
}
// Try to create readonly collection proxy
if (enumerable is IReadOnlyCollection <T> )
{
return(new ReadOnlyCollectionProxy <T>((IReadOnlyCollection <T>)enumerable));
}
// Handle error if explicit readonly
if (true == readOnly)
{
throw new ArgumentException(
"Cannot create readonly proxy: enumerable is not IReadOnlyCollection<T>."
);
}
throw new ArgumentException("Cannot create collection proxy: " +
"enumerable is neither an ICollection<T> nor an IReadOnlyCollection<T>.");
case CollectionProxyKind.List:
// If not explicit readonly
if (true != readOnly)
{
// Try to create mutable list proxy
if (enumerable is IList <T> )
{
return(new ListProxy <T>((IList <T>)enumerable));
}
// Handle error if explicit mutable
if (false == readOnly)
{
throw new ArgumentException(
"Cannot create mutable proxy: enumerable is not IList<T>."
);
}
}
// Try to create readonly list proxy
if (enumerable is IReadOnlyList <T> )
{
return(new ReadOnlyListProxy <T>((IReadOnlyList <T>)enumerable));
}
// Handle error if explicit readonly
if (true == readOnly)
{
throw new ArgumentException(
"Cannot create readonly proxy: enumerable is not IReadOnlyList<T>."
);
}
throw new ArgumentException("Cannot create list proxy: " +
"enumerable is neither an IList<T> nor an IReadOnlyList<T>.");
default:
throw new ArgumentOutOfRangeException("kind");
}
}
