BuildFeed/Code/DateTimeModelBinder.cs

using System;
using System.Globalization;
using System.Web.Mvc;

namespace BuildFeed
{
    public class DateTimeModelBinder : DefaultModelBinder
    {
        public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            var value = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
            DateTime retValue;
            bool success = DateTime.TryParse(value.AttemptedValue, CultureInfo.CurrentUICulture.DateTimeFormat, DateTimeStyles.AllowWhiteSpaces, out retValue);
            if(!success)
            {
                success = DateTime.TryParseExact(value.AttemptedValue, "yyMMdd-HHmm", CultureInfo.InvariantCulture, DateTimeStyles.AllowWhiteSpaces, out retValue);
            }

            return success ? retValue as DateTime? : null as DateTime?;
        }
    }
}