Eu tenho essa consulta, mas não consigo encontrar como defino meu WhereRestrictionOn como um OR. Agora eles funcionam como AND, mas eu quero um OU outro.

var privateInfo = Session.QueryOver<ConContact>()
            .JoinAlias(c => c.PrivateInfos, () => pi)
            .WhereRestrictionOn(c => c.FirstName).IsLike(_selectedFirstLetter + "%")
            .WhereRestrictionOn(c => c.LastName).IsLike(_selectedFirstLetter + "%") // todo: change to firstname OR lastname
            .Where(c => c.Status == ContactStatus.Approved)
            .Select(
                Projections.Property("pi.Id").WithAlias(() => sri.Id),
                Projections.Property("FirstName").WithAlias(() => sri.Name), //todo: get fullname here => Add concontact object in privateinfo
                Projections.Property("pi.Address").WithAlias(() => sri.Address),
                Projections.Constant("Contact").WithAlias(() => sri.Type)
            )
            .TransformUsing(Transformers.AliasToBean<SearchResultInfo>())
            .List<SearchResultInfo>()
            .ToList();

Qualquer ajuda é muito apreciada thx!

SOLUÇÃO:

var privateInfo = Session.QueryOver<ConContact>()
            .JoinAlias(c => c.PrivateInfos, () => pi)
            .Where(
                Restrictions.Disjunction()
                    .Add(Restrictions.Like("FirstName", _selectedFirstLetter + "%"))
                    .Add(Restrictions.Like("LastName", _selectedFirstLetter + "%"))
            )
            .Where(c => c.Status == ContactStatus.Approved)
            .Select(
                Projections.Property("pi.Id").WithAlias(() => sri.Id),
                Projections.Property("FirstName").WithAlias(() => sri.Name), //todo: get fullname here => Add concontact object in privateinfo
                Projections.Property("pi.Address").WithAlias(() => sri.Address),
                Projections.Constant(NewObjectType.Contact).WithAlias(() => sri.Type)
            )
            .TransformUsing(Transformers.AliasToBean<SearchResultInfo>())
            .List<SearchResultInfo>()
            .ToList();