protected abstract void VisitAndAlso(AndAlsoExpression expression);
protected virtual void VisitWhereNotIn(WhereNotInExpression expression)
{
IWhereExpression exp = new TrueExpression();
foreach (var value in expression.Values)
{
exp = new AndAlsoExpression(exp, new WhereNotEqualsExpression(null, expression.FieldName, value));
}
this.VisitWhere(exp);
}