C# EF Linq bitwise question - linq

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 using a class and passing in a value like 7 (Monday, Tuesday, Wednesday).
I want to return records that match any of those days
public List<Business> GetBusinesses(long daysOfWeek)
{
using (var c = Context())
{
return c.Businesses.Where(???).ToList();
}
}
Any help would be appreciated. Thanks!
EDIT
Ok, so I am attempting the following:
var b = new List<Business>();
var b1 = new Business(){DaysOfWeek = 3};
b.Add(b1);
var b2 = new Business() { DaysOfWeek = 2 };
b.Add(b2);
var decomposedList = new[]{1};
var l = b.Where(o => decomposedList.Any(day => day == o.DaysOfWeek)).ToList();
But l returns 0 results assuming in the decomposedList(1) I am looking for monday.
I created b1 to contain Monday and Tuesday.

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);
}