public static void AdjustToMvcLocalization(this ValidationAttribute attribute)
{
if (!(attribute is ExtendedValidationAttribute) &&
attribute.ErrorMessageResourceType == null &&
string.IsNullOrEmpty(attribute.ErrorMessageResourceName) &&
string.IsNullOrEmpty(attribute.ErrorMessage))
{
// attribute instances can be cached or static and this method can be called from multiple threads concurrently,
// so it's safer to lock during assignment (it's better to not make assumptions on the implementation of the setter of ErrorMessage);
// the preceding check can be done outside the lock as multiple assignments do no harm (the same constant value is assigned anyway)
lock (s_gate)
attribute.ErrorMessage = attribute.GetDefaultErrorMessage();
}
}