c# - Nhibernate empty query -

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i have next code

if (user != null)   query = query.where(item => item.user.id == user.id); else if (equipment != null)   query = query.where(item => false);// todo: add logic equipment

but nhibernate can't build expression tree item => false. someday expression change, must return empty query. there method solve problem?

assuming iqueryable of user, try this. 

if (user != null)   query = query.where(item => item.user.id == user.id); else if (equipment != null)   query = new list<user>().asqueryable();

edit:

op said iqueryover not iqueryiable, had @ source , queryover protected can't see how create empty 1 right now. suggestion use linq provider if can original answer work. if it's not possible ugly hack work now. 

if (user != null)                 query = query.where(item => item.user.id == user.id);             else if (equipment != null)                 query = query.where(item => item.user.id < 0 && item.user.id > 1);

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