Linq - 从DateTime选择日期 [英] Linq - Select Date from DateTime

问题描述

我有一个 Linq 结果，我只需从 DateTime中选择 Date 。

我的查询如下：

I have a Linq Result from which I need to select only Date from DateTime.
My Query goes like this :

var UserTemplates = (from xx in VDC.SURVEY_TEMPLATE
                     where xx.USER_ID == userid && xx.IS_ACTIVE == 1
                     select new
                     {
                       xx.TEMPLATE_ID,
                       xx.TEMPLATE_NAME,
                       //CREATED_DATE = xx.CREATED_DATE.Value.Date
                       //CREATED_DATE = EntityFunctions.TruncateTime(xx.CREATED_DATE)
                       xx.CREATED_DATE
                     }).ToList();

可能吗？
任何帮助将不胜感激。

Is that Possible? Any help would be greatly appreciated.

CREATED_DATE - `datetime` datatype

实际上，我将它绑定到一个控件，作为 DataSource ，控件是显示日期和时间。但是我只想显示 date 。

Actually,I'm Binding it to a Control as a DataSource and the control is displaying both Date and Time.But I want to display only date.

当我尝试使用 CREATED_DATE = xx.CREATED_DATE.Value.Date ，它发出如下错误：

When I'm trying with CREATED_DATE = xx.CREATED_DATE.Value.Date,It is giving an error like :

LINQ to Entities不支持指定的类型成员'Date'。
只支持初始化器，实体成员和实体导航属性
。

The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

推荐答案

如果是用于演示目的，则可以使用 DataFormatString 属性。例如，如果你将一个数据源绑定到一个GridView，你可以这样做：

If it is for presentation purpose, then you can use DataFormatString property. For Example, if you are binding a datasource to a GridView, you could do as;

<asp:BoundField DataField="CREATED_DATE" ...
     DataFormatString="{0:d}" ../>

否则，您可以使用 EntityFunctions.TruncateTime（），它返回没有时间部分的输入日期。

Else you can use EntityFunctions.TruncateTime() which returns the input date without the time portion.

EntityFunctions.TruncateTime(xx.CREATED_DATE)

您的查询将如下：

var UserTemplates = (from xx in VDC.SURVEY_TEMPLATE
                     where xx.USER_ID == userid && xx.IS_ACTIVE == 1
                     select new
                     {
                       xx.TEMPLATE_ID,
                       xx.TEMPLATE_NAME,
                       EntityFunctions.TruncateTime(xx.CREATED_DATE) //new like
                     }).ToList();

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