LINQ expression that will match multiple bulk inputs [duplicate]

Answer 1

Try with

var member = members.Where(member => divisons.Contains(member.Division) && department.Contains(member.Department)).ToList();

You have used Select clause, I have modiefied to work with Where.

Answer 2

This type of filtering is not supported directly by EF.

One possible solution is to build dynamically a predicate like this:

member => (member.Division == divisions[0] && member.Department == departments[0])
       || (member.Division == divisions[1] && member.Department == departments[1])
       ...
       || (member.Division == divisions[N-1] && member.Department == departments[N-1]);

Here is how you can do that:

var parameter = Expression.Parameter(typeof(Member), "member");
var predicate = Expression.Lambda<Func<Member, bool>>(
    Enumerable.Range(0, divisions.Length)
    .Select(i => new Expression[]
    {
        Expression.Equal(Expression.Property(parameter, "Division"), Expression.Constant(divisions[i])),
        Expression.Equal(Expression.Property(parameter, "Department"), Expression.Constant(departments[i])),
    }
    .Aggregate(Expression.AndAlso))
    .Aggregate(Expression.OrElse),
    parameter);
var query = members.Where(predicate);

Answer 3

This is similar to @Robert 's answer, but will filter the results to make sure the division and department are the same "pair":

int[] divisons = { 4, 6 }, departments = { 9, 3 };
var members = new[] { new { Division = 1, Department = 2 } }; // just for testing

var query = members.Where(m => divisons.Contains(m.Division) 
                         && departments.Contains(m.Department));

var member = query.AsEnumerable().Where(m => Array.IndexOf(divisons, m.Division) 
                        == Array.IndexOf(departments, m.Department));