public static IList CreateAndPopulateList(Type listType, Action <IList, bool> populateList)
{
ValidationUtils.ArgumentNotNull(listType, "listType");
ValidationUtils.ArgumentNotNull(populateList, "populateList");
IList list;
Type collectionType;
bool isReadOnlyOrFixedSize = false;
if (listType.IsArray)
{
// have to use an arraylist when creating array
// there is no way to know the size until it is finised
list = new List <object>();
isReadOnlyOrFixedSize = true;
}
else if (ReflectionUtils.InheritsGenericDefinition(listType, typeof(ReadOnlyCollection <>), out collectionType))
{
Type readOnlyCollectionContentsType = collectionType.GetGenericArguments()[0];
Type genericEnumerable = ReflectionUtils.MakeGenericType(typeof(IEnumerable <>), readOnlyCollectionContentsType);
bool suitableConstructor = false;
foreach (ConstructorInfo constructor in listType.GetConstructors())
{
IList <ParameterInfo> parameters = constructor.GetParameters();
if (parameters.Count == 1)
{
if (genericEnumerable.IsAssignableFrom(parameters[0].ParameterType))
{
suitableConstructor = true;
break;
}
}
}
if (!suitableConstructor)
{
throw new Exception("Read-only type {0} does not have a public constructor that takes a type that implements {1}.".FormatWith(CultureInfo.InvariantCulture, listType, genericEnumerable));
}
// can't add or modify a readonly list
// use List<T> and convert once populated
list = (IList)CreateGenericList(readOnlyCollectionContentsType);
isReadOnlyOrFixedSize = true;
}
else if (typeof(IList).IsAssignableFrom(listType))
{
if (ReflectionUtils.IsInstantiatableType(listType))
{
list = (IList)Activator.CreateInstance(listType);
}
else if (listType == typeof(IList))
{
list = new List <object>();
}
else
{
list = null;
}
}
else if (listType.IsGenericType && listType.GetGenericTypeDefinition() == typeof(IList <>))
{
list = CollectionUtils.CreateGenericList(ReflectionUtils.GetCollectionItemType(listType));
}
else
{
list = null;
}
if (list == null)
{
throw new Exception("Cannot create and populate list type {0}.".FormatWith(CultureInfo.InvariantCulture, listType));
}
populateList(list, isReadOnlyOrFixedSize);
// create readonly and fixed sized collections using the temporary list
if (isReadOnlyOrFixedSize)
{
if (listType.IsArray)
{
list = ToArray(((List <object>)list).ToArray(), ReflectionUtils.GetCollectionItemType(listType));
}
else if (ReflectionUtils.InheritsGenericDefinition(listType, typeof(ReadOnlyCollection <>)))
{
list = (IList)ReflectionUtils.CreateInstance(listType, list);
}
}
return(list);
}
public static IList CreateGenericList(Type listType)
{
ValidationUtils.ArgumentNotNull(listType, "listType");
return((IList)ReflectionUtils.CreateGeneric(typeof(List <>), listType));
}
