OData的$过滤substringof应用到字符串列表 [英] OData $filter substringof applied to a list of strings

问题描述

我有暴露了的IQueryable（串）的ASP.NET Web API控制器 - 这是描述的列表。这些字段可以在成千上万的顺序，所以我用 $顶部和 $跳过来只得到它的大块 - 工作正常。

I have an ASP.NET Web API Controller that exposes an IQueryable(Of String) - which is a list of descriptions. These fields can be in the order of tens of thousands, thus I use $top and $skip to only get a chunk of it - that works fine.

现在我想筛选这些结果，通过的OData substringof（'mydesc'，属性）过滤器。正如你所看到的，它需要我在属性命名要筛选通过。但是，因为我返回一个字符串列表，我实际上没有任何属性筛选依据。

Now I am trying to filter these results, through the OData substringof('mydesc',Property) filter. As you can see, it requires for me to pass in a Property name on which to filter. However, since I'm returning a list of strings, I don't actually have any properties to filter on.

这将导致服务器返回的错误一样
无属性或字段'的toString'类型'字符串'存在 - 当 $过滤器= substringof（ASD，的toString）名为。

This causes the server to return errors like No property or field 'tostring' exists in type 'String' - when called with $filter=substringof('asd',tostring).

如果我改变调用 $ =过滤substringof（'ASD'，''），不会引发任何错误，但没有任何结果。

If I change the call to $filter=substringof('asd',''), no errors are thrown, but no results either.

我的问题是，我能以某种方式格式化 $过滤器运营商找到我的字符串列表内子，没有寻找一个属性/字段，还是我去要声明一个类有一个属性，只需启用过滤功能？

My question is, can I somehow format the $filter operator to find substrings within my list of strings, without looking for a property/field, or am I going to have to declare a class with a single property, just to enable filtering?

推荐答案

自从我最后一次回答了这个事情已经改变了。 V3 OData的有查询使用'$它的原语集的支持。 Asp.net的Web API支持此语法为好。例如，在你的控制器就可以返回的IQueryable＆LT;串GT; 并发送类似

Things have changed since the last time I answered this. OData V3 has support for querying collection of primitives using '$it'. Asp.net Web API supports this syntax as well. For example, in your controller you can return IQueryable<string> and send a request like

$ =过滤字符串（'mydesc'，$），或者

$filter=substring('mydesc', $it) or

$ =过滤器长度（$吧）GE 5

$filter=length($it) ge 5

等。您也可以公开的其他元素的集合喜欢的IQueryable等。

etc. You can also expose collections of other primitives like IQueryable etc.

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