Model validations in ASP.NET WebAPI

FilterConfig.cs

    public class FilterConfig
    {
        public static void RegisterConfig(HttpConfiguration config)
        {
            // register global model validation filter
            config.Services.RemoveAll(typeof(System.Web.Http.Validation.ModelValidatorProvider), v => v is System.Web.Http.Validation.Providers.InvalidModelValidatorProvider);
            config.Filters.Add(new ValidationActionFilter());
        }
    }

ValidationActionFilter.cs

    public class ValidationActionFilter : ActionFilterAttribute
    {
        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            if (!actionContext.ModelState.IsValid)
            {
                var errors = new Dictionary<string, IEnumerable<string>>();
                foreach (KeyValuePair<string, ModelState> keyValue in actionContext.ModelState)
                {
                    errors[keyValue.Key] = keyValue.Value.Errors.Select(e => e.ErrorMessage);
                }

                actionContext.Response =
                    actionContext.Request.CreateResponse(HttpStatusCode.BadRequest, errors);
            }
        }
    }