Where子句不与parantheses一起工作 [英] Where clause not working with parantheses

问题描述

假设使用NH 3.4和RepositoryPattern的以下查询

  var list = _repository 
 .QueryOver（）
 .Where（x =>（x.Age> 20））//注意到parantheses 
 .Future（）
 .ToList（）; 
  

如果添加了这些缺陷，NH将无法正常工作，并导致SO异常。如果用<$ c替换 .Where（x =>（x.Age> 20）），那么

$ c> .Where（x => x.Age> 20）
按预期方式运作

任何线索为什么它不能与额外的偏食一起工作？

注意

图片。在生产中，我通过一个参数 Expression< Func< Person，bool>>来传递 .Where（...）

解决方案

我怀疑错误在那里：

 表达式< Func< MyClass，bool>> mc1 = x => （x.ID> 20）; 
 Expression< Func< MyClass，bool>> mc2 = x => x.ID> 20; 
 
 var body1 = mc1.Body.NodeType; // GreatThan 
 var body2 = mc2.Body.NodeType; // GreatThan 
  

括号被编译器删除。表达式树语言（类系统）中没有任何内容显式地表示括号。

Suppose the following Query using a NH 3.4 and RepositoryPattern

var list = _repository
     .QueryOver()
     .Where(x => (x.Age > 20))  // notice the parantheses
     .Future()
     .ToList();

Whith these parantheses added the NH is failing to work, and causes a SO exception.

If replacing .Where(x => (x.Age > 20)) with .Where(x => x.Age > 20) it works as expected.

Any clues on why it doesn't work with extra parantheses?

Note

This is a simplified scenario from the bigger picture. In production i'm passing that .Where(...) through a parameter Expression<Func<Person, bool>> where

解决方案

I have a doubt the error is there:

Expression<Func<MyClass, bool>> mc1 = x => (x.ID > 20);
Expression<Func<MyClass, bool>> mc2 = x => x.ID > 20;

var body1 = mc1.Body.NodeType; // GreatThan
var body2 = mc2.Body.NodeType; // GreatThan

The brackets are removed by the compiler. There is nothing in the Expression tree "language" (class system) to explicitly represent a bracket.

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