C＃EF Linq的按位问题 [英] C# EF Linq bitwise question

问题描述

好吧，例如，我使用的按位像这样的：星期一= 1，星期二= 2，星期三= 4，星期四= 8等等...

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

我使用的是实体框架类业务。

I am using an Entity Framework class of Business.

我使用的是类和传球像七日（星期一，星期二，星期三）。

I am using a class and passing in a value like 7 (Monday, Tuesday, Wednesday).

我要返回匹配任何的那些日子里记录

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();
         }
    }

任何帮助将是AP preciated。谢谢！

Any help would be appreciated. Thanks!

修改

好了，我试图以下内容：

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(); 

但升返回0结果假设在decomposedList（1）我找​​星期一。
我创建B1包含周一和周二。

But l returns 0 results assuming in the decomposedList(1) I am looking for monday. I created b1 to contain Monday and Tuesday.

推荐答案

使用按位与运算符＆安培; 到您想要的标志与实际的标志在数据库相结合，然后检查一个非零的结果。

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);
        }

如果你只是用OR然后组合过滤器值的数组 | 第一：

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);

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