在Linq中将Datetime转换为String的问题 [英] Problem with Converting Datetime to String in Linq

问题描述

我正在尝试将Nullable Datetime转换为我的Linq查询中的字符串。我收到此错误

Hi,

I'm trying to convert Nullable Datetime to string in my Linq Query. And I get this error

LINQ to Entities does not recognize the method 'System.Nullable`1[System.Int32] DatePart(System.String, System.Nullable`1[System.DateTime])' method, and this method cannot be translated into a store expression.

请帮帮我

Please help me

from p in TreatmentDetails
    select new
    {
        p.Id,
        p.TotalQty,
        p.Dose,
        p.IsStop,
        p.Note,
        p.TandFId,
        PrescriptionDate = SqlFunctions.DateName("day", p.PrescriptionDate).Trim() + "/" +
        SqlFunctions.StringConvert((double)p.PrescriptionDate.Value.Month).TrimStart() + "/" +
        SqlFunctions.DateName("year", p.PrescriptionDate)
                                    }).ToList();

推荐答案

您的错误似乎是从您的下一个代码部分生成的：

Your error seems to be generated from your next code section:

SqlFunctions.StringConvert((double)p.PrescriptionDate.Value.Month).TrimStart(); 

，特别是使用：

and especially the usage of:

p.PrescriptionDate.Value.Month

所以你应该使用以下方法修改这段代码：

So you should modify this code section by using:

DateName("month", p.PrescriptionDate).Trim()

LINQ不允许你进行任何类型的转换

你可以转换出linq代码

LINQ Does not allow you to do any type of converting
you can do your converting out of linq code

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