Question

Is there anyway to join LINQ where clauses as OR ?

var ints = new [] { 1, 3, 5, 7 };

var query = from i in ints select i;

query = query.Where (q => q == 3);

query = query..Where (q => q == 7);

What I want is the ability to dynamically add where clauses but make them use OR instead of AND

Answer 1

If you want to stay with your strong-typing Linq queries you should look into LinqKit and predicate building. I have used this for something similar and found it to work well with And / Or stacking of filters.

Check out the C#4.0/3.0 in a Nutshell excerpt for more in depth info. Here is a snip from my code:

        //Setup the initial predicate obj then stack on others:
        basePredicate = basePredicate.And(p => false);
        var predicate1 = PredicateBuilder.True<Person>();

        foreach (SearchParms parm in parms)
        {
            switch (parm.field)
            {
                case "firstname":
                    predicate1 = predicate1.And(p => p.FirstName.Trim().ToLower().Contains(sValue));
                    break;
                //etc...
            }

        }
        //Run a switch based on your and/or parm value to determine stacking:
        if (Parm.isAnd) {
             basePredicate = basePredicate.And(predicate1);
        } else {
             basePredicate = basePredicate.Or(predicate1);
        }