public static IReadOnlyList <T> WrapAsIReadOnlyList <T>(this IEnumerable <T> source)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (source is T[] array)
{
#if LESSTHAN_NET45
return(new ReadOnlyCollectionEx <T>(array));
#else
return(ArrayEx.AsReadOnly(array));
#endif
}
if (source is ListEx <T> listEx)
{
return(listEx.AsReadOnly());
}
#if GREATERTHAN_NET45 || TARGETS_NETCORE || TARGETS_NETSTANDARD
if (source is List <T> list)
{
return(list.AsReadOnly());
}
#endif
if (source is IReadOnlyList <T> result)
{
return(result);
}
return(EnumerationList <T> .Create(source));
}
public static IReadOnlyCollection <T> AsIReadOnlyCollection <T>(this IEnumerable <T>?source)
{
if (source == null)
{
return(EmptyCollection <T> .Instance);
}
if (source is T[] array)
{
#if LESSTHAN_NET45
return(new ReadOnlyCollectionEx <T>(array));
#else
return(ArrayEx.AsReadOnly(array));
#endif
}
if (source is ListEx <T> listEx)
{
return(listEx.AsReadOnly());
}
#if GREATERTHAN_NET45 || TARGETS_NETCORE || TARGETS_NETSTANDARD
if (source is List <T> list)
{
return(list.AsReadOnly());
}
#endif
if (source is IReadOnlyCollection <T> result)
{
return(result);
}
return(EnumerationList <T> .Create(source));
}