使用实体框架中的OR和Contains进行动态查询 [英] Dynamic query using OR and Contains in Entity Framework

问题描述

给出一个这样的字符串：

  var filterOptions =First Bank; 
  

还有一个具有Grantee列和Grantor列的表，如何使用EF创建查询这将产生以下where子句：

  ...其中（授予者喜欢'％First％'和Grantor like'％Bank ％'）或（受让人像'％First％'和受让人像'％Bank％'）
  

请记住，filterOptions是一个传入的parm，所以它可以很容易地包含3或4个单词，而不仅仅是两个...在这种情况下，每个列都需要额外的类似子句。

如果不是OR的一部分，我会执行以下操作（这将有助于更好地了解我正在努力完成的任务。

  foreach（filterOptions中的var word）
 {
 var text =％+ word +％; 
 query = query.Where（r => SqlMethods.Like（r.Grantee，text））; 
} 
  

像我说的，它试图添加OR部分与另一个col

解决方案

首先，阅读下面的博客，那么你将会知道如何做OR操作：
http://www.albahari.com/nutshell/predicatebuilder.aspx

其次，如果您使用实体框架，请阅读另一个博客，它对Entity Framework有更好的predicatebuilder实现：
http://petemontgomery.wordpress.com/2011/02/10/a-niversiversal- predicatebuilder /

Given a string like this:

var filterOptions = "First Bank";

And a table that has a Grantee column and a Grantor column, how do I create a query with EF that will generate the following where clause:

... where (Grantor like '%First%' and Grantor like '%Bank%') or (Grantee like '%First%' and Grantee like '%Bank%')

Keep in mind that filterOptions is a parm that is passed in, so it could just as easily contain 3 or 4 words rather than just two ... in which case each column would need additional like clauses.

If it weren't for the OR part of this, I would do the following (which will help give a better idea of what I'm trying to accomplish.

foreach(var word in filterOptions)
{
    var text = "%" + word + "%";
    query = query.Where(r => SqlMethods.Like(r.Grantee,text));
}

Like I said, its trying to add the OR portion with the other column that throws me for a loop.

解决方案

First, Read the blog below, then you will know how to do the OR operation: http://www.albahari.com/nutshell/predicatebuilder.aspx

Second, If you're using Entity Framework, read another blog, it has a better "predicatebuilder" implematation for Entity Framework: http://petemontgomery.wordpress.com/2011/02/10/a-universal-predicatebuilder/

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