LINQ to SQL中的多个defered WHERE子句表达式

本文是小编为大家收集整理的关于LINQ to SQL中的多个defered WHERE子句表达式的处理/解决方法，可以参考本文帮助大家快速定位并解决问题，中文翻译不准确的可切换到English标签页查看源文。

中文
English

问题描述

也许是一个简单的问题，我正在尝试从名称列包含所有搜索词数组的表中获取结果.我正在创建一个查询并遍历我的搜索字符串，每次分配 query = query.Where(...);.似乎只使用了最后一个术语，我想是因为我每次都试图限制同一个字段.如果我在每次迭代中调用 .ToArray().AsQueryable() ，我可以获得我正在寻找的累积限制行为，但是是否有一种简单的方法可以仅使用延迟运算符来做到这一点?

谢谢！

推荐答案

如果你正在做类似的事情:

foreach (int foo in myFooArray)
{
  query = query.where(x => x.foo == foo);
}

...那么它将只使用最后一个，因为每个 where 条件都包含对 'foo' 循环变量的引用.

如果您正在这样做，请将其更改为:

foreach (int foo in myFooArray)
{
  int localFoo = foo;
  query = query.where(x => x.foo == localFoo);
}

...一切都会好起来的.

如果这不是正在发生的事情，请提供您正在做的事情的代码示例...

本文地址：https://www.itbaoku.cn/post/1556838.html

百度翻译此文有道翻译此文

问题描述

Maybe a simple question, I'm trying to get a result from a table where the Name column contains all of an array of search terms. I'm creating a query and looping through my search strings, each time assigning the query = query.Where(...);. It appears that only the last term is being used, I supposed because I am attempting to restrict the same field each time. If I call .ToArray().AsQueryable() with each iteration I can get the cumlative restrinction behavior I'm looking for, but it there an easy way to do this using defered operators only?

Thanks!

推荐答案

If you're doing something like:

foreach (int foo in myFooArray)
{
  query = query.where(x => x.foo == foo);
}

...then it will only use the last one since each where criteria will contain a reference to the 'foo' loop variable.

If this is what you're doing, change it to:

foreach (int foo in myFooArray)
{
  int localFoo = foo;
  query = query.where(x => x.foo == localFoo);
}

...and everything should be fine again.

If this is not what is happening, please provide a code sample of what you're doing...

上一篇：LINQ到XML是否在查询期间加载整个XML文档?

下一篇：无法将方法组分配给ASP.NET，LINQ，C#中隐式型的本地变量