如何在“或”上拆分或连接 linq 查询（不使用联盟）？

发布于 2024-12-10 11:04:31 字数 752 浏览 1 评论 0原文

假设您正在搜索具有两个布尔属性 A 和 B 的某个对象。

如果您有两个 linq 查询怎么办：

IQueryable<ObjectType> query = getIQueryableSomehow()
query.Where(x => x.A);

IQueryable<ObjectType> query2 = getIQueryableSomehow()
query2.Where(x => x.B);

如何将这些查询连接在一起，以便它们与此等效？：

IQueryable<ObjectType> query3 = getIQueryableSomehow()
query3.Where(x => x.A || x.B)

我想使用 query3 = query.Union (query2)，但遗憾的是我的 Linq 提供者联合不受支持。

我将 x => 的情况分开xA&& xB 通过链接 where 子句。这就是我的意思：

IQueryable<ObjectType> query = getIQueryableSomehow();
query = query.Where(x => x.A);
query = query.Where(x => x.B);

对于 or 情况是否有类似的解决方法？

谢谢，

艾萨克

原文

Suppose you're searching some object with two boolean properties, A and B.

What if you have two linq queries:

IQueryable<ObjectType> query = getIQueryableSomehow()
query.Where(x => x.A);

IQueryable<ObjectType> query2 = getIQueryableSomehow()
query2.Where(x => x.B);

How can I join these queries together so that they are equivalent to this?:

IQueryable<ObjectType> query3 = getIQueryableSomehow()
query3.Where(x => x.A || x.B)

I would like to use query3 = query.Union(query2), but sadly in my Linq provider union is not supported.

I split up the case for x => x.A && x.B by chaining the where clause. This is what I mean:

IQueryable<ObjectType> query = getIQueryableSomehow();
query = query.Where(x => x.A);
query = query.Where(x => x.B);

Is there some similar workaround for the or case?

Thanks,

Isaac

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腹黑女流氓 2024-12-17 11:04:32

如果您的 LINQ 提供程序不支持 Union 运算符，您始终可以首先使用 ToArray() 具体化查询结果，然后使用 LINQ-to-objects 提供程序来执行它支持的并集，如下所示

IQueryable<ObjectType> query = getIQueryableSomehow() 
query.Where(x => x.A); 

IQueryable<ObjectType> query2 = getIQueryableSomehow() 
query2.Where(x => x.B); 

IQueryable<ObjectType> query3 = query.ToArray().AsQueryable<ObjectType>().Union(query2);

：只要你联合的结果不是太大。

If your LINQ provider doesn't support the Union operator, you can always first materialize the query results using ToArray(), and then use the LINQ-to-objects provider to perform the union, which it supports, like so:

IQueryable<ObjectType> query = getIQueryableSomehow() 
query.Where(x => x.A); 

IQueryable<ObjectType> query2 = getIQueryableSomehow() 
query2.Where(x => x.B); 

IQueryable<ObjectType> query3 = query.ToArray().AsQueryable<ObjectType>().Union(query2);

This will work well as long as your results being unioned are not too large.

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痴情 2024-12-17 11:04:31

使用谓词生成器

IQueryable<ObjectType> query = getIQueryableSomehow();
var predicate = PredicateBuilder.False<ObjectType>();
predicate = predicate.Or(x => x.A);
predicate = predicate.Or(x => x.B);

var list = query.Where(predicate).ToList();

using Predicate Builder

IQueryable<ObjectType> query = getIQueryableSomehow();
var predicate = PredicateBuilder.False<ObjectType>();
predicate = predicate.Or(x => x.A);
predicate = predicate.Or(x => x.B);

var list = query.Where(predicate).ToList();

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