There are a few ways to go about this:
Apply the "where" to the original query each time, and then
Union()
the resulting queries.var queries = new List<IQueryable<Session>>(); if (!String.IsNullOrEmpty(Division)) { queries.Add(sessions.Where(y => y.session.SESSION_DIVISION.Any(x => x.DIVISION.ToUpper().Contains(SearchContent)))); } if (!String.IsNullOrEmpty(Room)) { // this shoudl be OR queries.Add(sessions.Where(y => y.session.ROOM.ToUpper().Contains(SearchContent))); } if (!String.IsNullOrEmpty(course)) { // this shoudl be OR queries.Add(sessions.Where(y => y.session.COURSE.ToUpper().Contains(SearchContent))); } sessions = queries.Aggregate(sessions.Where(y => false), (q1, q2) => q1.Union(q2));
Do Expression manipulation to merge the bodies of your lambda expressions together, joined by
OrElse
expressions. (Complicated unless you've already got libraries to help you: after joining the bodies, you also have to traverse the expression tree to replace the parameter expressions. It can get sticky. See this post for details.- Use a tool like PredicateBuilder to do #2 for you.