/// <summary>
/// Returns a list of cultures that have any validation errors
/// </summary>
/// <param name="modelState"></param>
/// <param name="localizationService"></param>
/// <param name="cultureForInvariantErrors">The culture to affiliate invariant errors with</param>
/// <returns>
/// A list of cultures that have validation errors. The default culture will be returned for any invariant errors.
/// </returns>
internal static IReadOnlyList <string> GetCulturesWithErrors(this System.Web.Http.ModelBinding.ModelStateDictionary modelState,
ILocalizationService localizationService, string cultureForInvariantErrors)
{
var propertyCultureErrors = modelState.GetCulturesWithPropertyErrors(localizationService, cultureForInvariantErrors);
//now check the other special culture errors that are
var genericCultureErrors = modelState.Keys
.Where(x => x.StartsWith("_content_variant_") && x.EndsWith("_"))
.Select(x => x.TrimStart("_content_variant_").TrimEnd("_"))
.Where(x => !x.IsNullOrWhiteSpace())
//if it's marked "invariant" than return the default language, this is because we can only edit invariant properties on the default language
//so errors for those must show up under the default lang.
.Select(x => x == "invariant" ? cultureForInvariantErrors : x)
.WhereNotNull()
.Distinct();
return(propertyCultureErrors.Union(genericCultureErrors).ToList());
}