C# EF Linq bitwise question

Question

Ok for example, I am using bitwise like such: Monday = 1, Tuesday = 2, Wednesday = 4, Thursday = 8 etc...

I am using an Entity Framework class of Business.

I am

Answer 1

Use the bitwise and operator & to combine your desired flags with the actual flags in the database and then check for a non-zero result.

        var b1 = new { DaysOfWeek = 3 };
        var b2 = new { DaysOfWeek = 2 };
        var b = new[] { b1, b2 };
        var filter = 1;

        var l = b.Where(o => (filter & o.DaysOfWeek) != 0);
        foreach (var x in l)
        {
            Console.WriteLine(x);
        }

If you have an array of filter values simply combined then with an OR | first:

        var filterArray = new []{1, 4};
        var filter = filterArray.Aggregate((x, y) => x | y);

Answer 2

You must decompose the long value(bitflagged enum will be better) to it's parts then pass it to Where

return c.Businesses.Where(o=> DecomposeDays(dayParam).Any(day => day==o)).ToList();

EDIT: decompose method:

private static IEnumerable<byte> DecomposeDays(byte dayParam)
{
    var daysOfWeek = new List<byte> { 1, 2, 4, 6, 8 ,16};
    return daysOfWeek.Where(o => (o & dayParam) == dayParam);
}