var groupedByWeek = salesOrdersList
    .GroupBy(i => i.DueDate.AddDays(-(int)i.DueDate.DayOfWeek));

但是我得到一个“黄色死亡屏幕”,错误：

LINQ to Entities does not recognize the method ‘System.DateTime AddDays(Double)’ method,and this method cannot be translated into a store expression.

理想情况下我想说

var groupedByWeek = salesOrdersList.GroupBy(i => i.DueDate.WeekNumber);

但生活并不那么容易！

有没有人知道使用Linq to Entities的周数的方法？