c# 4.0 - Create linq Query dynamically -

i have problem create condition inside linq query (where). condition inside created based on condition. want filter list of indice based on 2 property (id_indice_prix, date_indice). can filter on both of them or one. have suggestion. doing rows database linq entites , if condtion filter based on condition:

   var listeindiceactualisationprix = unitofwork.indices_actualisation_prix.tolist();          if (idindiceprix != 0)              listeindiceactualisationprix = listeindiceactualisationprix.where(x => x.id_indice_prix == idindiceprix).tolist();           if(annee !=0)             listeindiceactualisationprix = listeindiceactualisationprix.where(x => x.date_indice.value.year == annee).tolist(); 

don't put .tolist() every time. when call .tolist(), query executed. build query dynamically without .tolist(), , @ end of if statements, execute .tolist() query database appropriate where statements.