LINQ到实体组(按周数) [英] Linq to Entities group by week number

问题描述

我对实体使用ASP.NET v4.5和linq 我正在尝试使用以下代码按周对数据进行分组

I am using ASP.NET v4.5 and linq to entities I am trying to group my data by week using the below code

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

但是我得到一个带有错误的死亡黄屏":

However I am getting a "yellow screen of death" with the error:

LINQ to Entities无法识别方法'System.DateTime AddDays(Double)'，并且该方法无法转换为商店表达式.

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，我想输入

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

但是生活并不那么轻松！

But life isn't that easy!

有人知道在Linq to Entities中使用周数的方法吗?

Does anyone know a way of using week numbers with Linq to Entities?

推荐答案

使用 SqlFunctions.DatePart() 方法:

Use SqlFunctions.DatePart() method:

var groupedByWeek = salesOrdersList.GroupBy(i => SqlFunctions.DatePart("week", i.DueDate));

它将DATEPART sql函数调用添加到生成的SQL查询中.

It will add DATEPART sql function call into generated SQL query.

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