动态LINQ日期时间比较字符串构建-Linq To Entities [英] Dynamic LINQ DateTime Comparison String Building - Linq To Entities

问题描述

我正在使用Scott Guthrie的动态LINQ库以及Entity Framework和C#.

I'm using the dynamic LINQ library by Scott Guthrie together with Entity Framework and C#.

我必须基于几个因素将where字符串构建为变量，然后将字符串变量传递给where子句.由于某些原因，这将起作用:

I have to build my where string into a variable based on several factors and then pass the string variable to the where clause. For some reason, this will work:

ContactList = ContactList.Where("DateAdded >= @0", DateTime.Parse("12/1/2012"));

但这不起作用

string WhereClause = string.Format("DateAdded >= {0}", DateTime.Parse("12/1/2012"));
ContactList = ContactList.Where(WhereClause);

如上所述，我需要在传递变量的版本中使用它.有人知道第二个为什么不起作用吗?

As mentioned, I need to use it in the version of passing the variable. Anyone know why the second doesn't work?

提前谢谢！

推荐答案

似乎我要使用当前的DynamicLINQ库无法实现. Tilak在下面很好地概述了它不起作用的原因.

It seems what I was trying to do is not possible with the current DynamicLINQ library. The reason it didn't work was well outlined below by Tilak.

我的解决方案是修改DynamicLINQ库，以允许将查询写为字符串并传递给Date/Time数据类型的where子句. Paul Hatcher在此处找到了修改: LINQ TO SQL，具有DATE类型字段的动态查询

My solution was to modify the DynamicLINQ library to allow the query to be written as a string and passed to the where clause for Date/Time datatypes. The modification was found here by Paul Hatcher: LINQ TO SQL, Dynamic query with DATE type fields

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