LINQ is it possible to add where clauses dynamically

Question

I want to search my db with different keys. According to the input, there may be 1 key to 10 keys. Is there a way to add OR/AND clauses to my Linq query dynamically?

Answer 1

For AND clauses it is simple:

var feedList = from feed in ctx.Feed;
foreach(var key in keys){
    feedList = feedList.Where(x=> content.contains(key));
}
var resultQuery = feedList.Select(x=> new {....});

For OR you will need to use Expressions or try LinqKit and its predicates :

var predicate = PredicateBuilder.False();
foreach(var key in keys){
    predicate = predicate.Or(x=> content.contains(key));
}
var resultQuery = ctx.Feed.Where(predicate).Select(x=> new {....});