public abstract class DataErrorInfo :ObservableObject, IDataErrorInfo
    {
        [Browsable(false)]
        public string Error
        {
            get
            {
                var errors = ValidationHelper.GetErrors(this);
                return string.Join(Environment.NewLine, errors);
            }
        }

        public string this[string columnName]
        {
            get
            {
                var errors = ValidationHelper.ValidateProperty(this, columnName);
                return string.Join(Environment.NewLine, errors);
            }
        }
    }