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动态构建查询表达式或

[英]Building up a query expression dynamically or

原文 2011-01-10 13:06:10 4 1 c#/ linq/ entity-framework

I'm looking at porting logic from a stored procedure to an EF model. 我正在研究将逻辑从存储过程移植到EF模型。 The stored procedure optionally accepted a list of departments which would be searched. 该存储过程可以选择接受要搜索的部门列表。 Effectively I'm dynamically building the search criteria (or trying to..). 有效地，我正在动态地建立搜索条件（或试图..）。

I've got a parameter class which contains a List< string> DeptCodes which is passed to my Searcher class. 我有一个参数类，其中包含一个List< string> DeptCodes ，该参数传递给我的Searcher类。 I'm applying the constraints against a set of data IQueryable< SearchResult> dataList . 我将约束应用于一组数据IQueryable< SearchResult> dataList 。 If DeptCodes contains any items I want to apply a chained set of or-ed constraints (in SQL where (DeptCode in 'ABC' or DeptCode in 'DEF') ). 如果DeptCodes包含任何项目，我想应用一组链式or-ed约束（在SQL where (DeptCode in 'ABC' or DeptCode in 'DEF') ）。

I guess I want to create an expression tree but I'm not sure where to start (my LINQ skills aren't quite up to speed at the moment). 我想我想创建一个表达式树，但是我不确定从哪里开始（我的LINQ技能目前还不太快）。 Can anyone point me in the right direction or give me a little sample to get me started? 谁能指出我正确的方向，还是给我一些示例以帮助我入门？

Thanks in advance 提前致谢

1 个解决方案

I think PredicateBuilder could be a good solution. 我认为PredicateBuilder可能是一个很好的解决方案。

Try to look at it . 尝试看一下。

在 python 中动态构建表达式 - Building an expression in python dynamically

动态构建表达式树 - Dynamically building an expression tree

使用类型转换动态构建表达式树 - Building expression tree dynamically with typecasting

为 EF Where() 子句动态构建表达式树 - Dynamically building an expression tree for an EF Where() clause

在xy平面中动态建立矩阵 - Building up a matrix dynamically in the xy plane

使用表达式树循环构建动态查询 - Building dynamic query in a loop using Expression trees

建立基于布尔的LINQ查询 - Building up a LINQ query based on bools

动态构建功能 <Tn,T> 使用Expression的动态物体 - Dynamically building Func<Tn,T> with a dynamic body using Expression

构建表达式树以在LINQ中动态排序字典字典 - Building expression tree to dynamically sort a dictionary of dictionaries in LINQ

动态构建Linq以使用连锁属性实现Lambda表达式 - Dynamically Building Linq to Entities Lambda Expression with Concatenated Properties

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相关问题 在 python 中动态构建表达式 - Building an expression in python dynamically 动态构建表达式树 - Dynamically building an expression tree 使用类型转换动态构建表达式树 - Building expression tree dynamically with typecasting 为 EF Where() 子句动态构建表达式树 - Dynamically building an expression tree for an EF Where() clause 在xy平面中动态建立矩阵 - Building up a matrix dynamically in the xy plane 使用表达式树循环构建动态查询 - Building dynamic query in a loop using Expression trees 建立基于布尔的LINQ查询 - Building up a LINQ query based on bools 动态构建功能 <Tn,T> 使用Expression的动态物体 - Dynamically building Func<Tn,T> with a dynamic body using Expression 构建表达式树以在LINQ中动态排序字典字典 - Building expression tree to dynamically sort a dictionary of dictionaries in LINQ 动态构建Linq以使用连锁属性实现Lambda表达式 - Dynamically Building Linq to Entities Lambda Expression with Concatenated Properties

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