public MappingConfigurationViewModelFactory (IReadOnlyList<string> availableCategories, ICurrentOptions currentOptions)
{
if (availableCategories == null)
throw new ArgumentNullException (nameof (availableCategories));
if (currentOptions == null)
throw new ArgumentNullException (nameof (currentOptions));
_availableCategories = availableCategories;
_currentOptions = currentOptions;
}