@Html.DropDownListFor(model => model.AccountType, new SelectList(Enum.GetNames(typeof(Enums.AccountType))))

public enum AccountType : byte
{
   مدیر = 0,
   کاربر_حقیقی = 1,
   کاربر_حقوقی = 2,
}

namespace MvcApplication1.Models
{
    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public abstract class PropertyBindAttribute : Attribute
    {
        public abstract bool BindProperty(ControllerContext controllerContext,
        ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor);
    }

    public class ExtendedModelBinder : DefaultModelBinder
    {
        protected override void BindProperty(ControllerContext controllerContext,
            ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor)
        {
            if (propertyDescriptor.Attributes.OfType<PropertyBindAttribute>().Any())
            {
                var modelBindAttr = propertyDescriptor.Attributes.OfType<PropertyBindAttribute>().FirstOrDefault();

                if (modelBindAttr.BindProperty(controllerContext, bindingContext, propertyDescriptor))
                    return;
            }

            base.BindProperty(controllerContext, bindingContext, propertyDescriptor);
        }
    }
}

    public class AccountTypeBindAttribute : PropertyBindAttribute
    {
        public override bool BindProperty(ControllerContext controllerContext,
            ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor)
        {
            if (propertyDescriptor.PropertyType == typeof(byte))
            {
                HttpRequestBase request = controllerContext.HttpContext.Request;

                byte accountType = (byte)Enum.Parse(typeof(Enums.AccountType), request.Form["AccountType"]);
                propertyDescriptor.SetValue(bindingContext.Model, accountType);

                return true;
            }
            return false;
        }
    }  

[AccountTypeBindAttribute]
public byte AccountType { get; set; }

ModelBinders.Binders.DefaultBinder = new ExtendedModelBinder();

   The field نوع کاربر : must be a number.     

@Html.DropDownListFor(model => model.AccountType, new SelectList(Enum.GetNames(typeof(Enums.AccountType))),new Dictionary<string, object>() {{ "data-val", "false" }})