使用对象列表，“过滤器"过滤器如何知道要匹配哪些字段? [英] With List of objects how can the `filter` filter know which fields to match on?

问题描述

我在 json 响应上使用 filter:query 来过滤.一切正常.当我将 json 响应转换为适当的类时，过滤器停止工作.使用查询匹配类上的字段的方法是什么?这是我应该创建自己的自定义@NgFilter 的情况吗?

I was using filter:query on a json response to filter. Everything worked fine. When I turned the json response into proper classes the filter stopped working. What is the approach to use query to match fields on a class? Is this the situation where I should then create my own custom @NgFilter?

推荐答案

对于 AngularDart filter filter 您可以通过将字段名称作为传递来指定要匹配的字段地图键.

For the AngularDart filter filter you specify which fields to match on by passing the field names as the keys to a map.

让我们使用 AngularDart 教程 食谱类为例:

Let us use the AngularDart tutorial Recipe class as an example:

  class Recipe { String id; String name; String category; ... }

您可以过滤，例如，在 Recipe.name 上使用字符串 ctrl.nameFilterString 写:

You can filter, e.g., on Recipe.name using the string ctrl.nameFilterString write:

  <li ng-repeat="recipe in ctrl.recipes | filter:{name:ctrl.nameFilterString}">

这里是摘自 filter API doc 解释了 filter 如何解释其参数.IE.在

Here is an excerpt from the filter API doc that explains how filter interprets its argument. I.e. in

  v | filter:x

参数 x 可以是一个

• String、bool 和 num:只有 List 中的项目直接匹配这个表达式，任何 Maps 的项目与此项目和包含一个列表的项目匹配的值返回匹配项.

• String, bool and num:  Only items in the List that directly match this expression, items that are Maps with any value matching this item and items that are Lists containing a matching items are returned.

Map:这定义了一个模式映射.过滤器特定输入列表中包含的对象的属性.例如{name:"M", phone:"1"} 谓词将返回项目列表其中具有包含M"的属性 name 和属性 phone包含1".可以使用特殊的属性名称 $(如在 {$: "text"} 中)接受与对象的任何属性的匹配.这相当于简单的子串与 String 匹配，如如上所述.

Map:  This defines a pattern map.  Filters specific properties on objects contained in the input List.  For example {name:"M", phone:"1"} predicate will return a list of items which have property name containing "M" and property phone containing "1".  A special property name, $, can be used (as in {$: "text"}) to accept a match against any property of the object. That's equivalent to the simple substring match with a String as described above.

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