When you validate

Please return why it didn’t validate by reference. Like this

public bool ValidateSearchParameters(AdvertSearchParameters advertSearchParameters, ref string errorString)
        {
 
            if (advertSearchParameters.IsTextSearch)
            {
                if (advertSearchParameters.TextKeywords.Length < 5) //TODO : will be provided by config
                {
                    errorString = "Must be more than 5 charachter.";
                    return false;
                }
            }

}

Life runs on code :)