private T ExtractEnum <T>(ControllerContext controllerContext, ModelBindingContext bindingContext, string pattern)
where T : struct
{
if (!typeof(T).IsEnum)
{
throw new ArgumentException("Expected an enumeration.");
}
var keys =
controllerContext.HttpContext.Request.Form.AllKeys.Where(
k => System.Text.RegularExpressions.Regex.IsMatch(k, pattern + "\\[.+\\]"));
var values = new List <T>();
foreach (var key in keys)
{
values.Add((T)Enum.Parse(typeof(T), controllerContext.HttpContext.Request.Form[key]));
}
bindingContext.ModelState.Remove(pattern);
return(EnumHelpers.Combine(values));
}