grails如何检查值是否在gsp的列表中

Question

I'm getting a list back from my action that I want to check against another value in the GSP. 我从操作中获取了一个列表，该列表要与GSP中的另一个值进行比较。 I want to be able to see if the value is in the list that gets returned. 我希望能够查看该值是否在返回的列表中。 I know you can do direct comparison 我知道你可以直接比较

<g:if a="a">

but what I am looking for is a string in array comparison 但是我正在寻找的是数组比较中的字符串

<g:if a in [a,b,c,d]>

Need something like 需要类似的东西

<g:if test="${myList}.contains(${username})}">

Tried: 尝试过：

<g:if test="${myList.contains(username)}">

and everything is returning false (even when contains should be true) 一切都返回false（即使包含应该为true）

Test Data: 测试数据：

        ${myList.keySet()}
        ${username}

<g:if test="${failedToSync.keySet().contains(username)}">
                <li>${username} yes</li>
            </g:if>
            <g:else>
                <li>${username} no</li>         
            </g:else>

outputs: 输出：

[a] b
b no
[a] a
a no

Additional info: 附加信息：

"${username.stripIndent() == failedToSync.keySet()[0]}" returns true "${username.stripIndent() == failedToSync.keySet()[0]}"返回true

<g:if test="${(failedToSync.keySet()).contains(username.stripIndent())}"> returns false

Answer 1

In Groovy you can use .contains on any collection. 在Groovy中，您可以在任何集合上使用.contains 。 So, for your case 所以，对于你的情况

<g:if test="${['a', 'b', 'c'].contains('a')}">
...
</g:if>

Answer 2

You could use a custom tag if you like: 如果愿意，可以使用自定义标签：

grails-app/taglib/com/demo/StackOverflowTagLib.groovy

package com.demo

class StackOverflowTagLib {
    static namespace = 'my'

    // ...

    def isInList = { attrs, body ->
        def val = attrs.val
        def list = attrs.collection
        if(val in list) {
            out << body()
        }
    }
}

grails-app/views/demo/index.gsp

<html>
<body>
    <my:isInList val="Jeff" collection="${names}">
        Yep, Jeff was in there.
    </my:isInList>
</body>
</html>

grails-app/controllers/com/demo/DemoController.groovy

package com.demo

class DemoController {

    def index() {
        [names: ['Jeff', 'Betsy', 'Zack', 'Jake']]
    }
}

I hope that helps. 希望对您有所帮助。

Answer 3

I think you have answered your own question: Yes, like 我认为您已经回答了自己的问题：是的，就像

<g:if test="${'a' in ['a','b','c','d']}">
    Some Content
</g:if>

grails如何检查值是否在gsp的列表中

问题描述

3 个解决方案

解决方案1
2 2014-06-30 17:42:58

解决方案2
1 2014-06-30 18:37:26

解决方案3
0 2014-06-30 17:47:57

grails如何检查值是否在gsp的列表中

问题描述

3 个解决方案

解决方案1 2 2014-06-30 17:42:58

解决方案2 1 2014-06-30 18:37:26

解决方案3 0 2014-06-30 17:47:57

解决方案1
2 2014-06-30 17:42:58

解决方案2
1 2014-06-30 18:37:26

解决方案3
0 2014-06-30 17:47:57