中的Grails (Grails in )

中的Grails (Grails in )

我在.gsp文件中有这个<g:select> 。 但是，与任何普通的<g:select>不同，如果满足某个条件，则该属性将具有disabled="" 。

遵循以下代码：

<g:select name="test" from="${["foo1","foo2"]}" <g:if test="${true}">disabled=""</g:if> />

它返回了一个错误： Grails tag [g:select] was not closed

但是当我把它改成这个时：

<g:select name="test" from="${["mu1","mu2","mu3"]}" ${ if(true) { println "disabled=\"\"" } }/>

它返回了此错误： Attribute value must be quoted.

这两个错误消息都在异常下， org.codehaus.groovy.grails.web.taglib.exceptions.GrailsTagException

问题是我们如何才能使这项工作成功？ 没有使用自定义TagLib，是否有可能的答案？

I have this <g:select> in a .gsp file. But unlike any ordinary <g:select>'s this one would have the attribute disabled="" if a certain condition is met.

Following the code:

<g:select name="test" from="${["foo1","foo2"]}" <g:if test="${true}">disabled=""</g:if> />

It returned an error: Grails tag [g:select] was not closed

But when I change it into this:

<g:select name="test" from="${["mu1","mu2","mu3"]}" ${ if(true) { println "disabled=\"\"" } }/>

It returned this error: Attribute value must be quoted.

Both of the error message are under the exception, org.codehaus.groovy.grails.web.taglib.exceptions.GrailsTagException

The question is how could we make this work? Is there a possible answer without using a custom TagLib?

最满意答案

GSP表单字段标记将disabled视为布尔属性，因此您可以这么说

<g:select .... disabled="${true}" />

通常你应该能够在通常的Groovy-truth规则下使用任何表达式，但我相信它为字符串“true”和“false”提供了一个特例（后者在Groovy-truth规则下通常被认为是非-empty string）。 如果有疑问你可以随时说

disabled="${(someExpression) as boolean}"

The GSP form field tags treat disabled as a boolean property, so you can say

<g:select .... disabled="${true}" />

Generally you should be able to use any expression under the usual Groovy-truth rules but I believe it makes a special case for the strings "true" and "false" (the latter would normally be considered true under Groovy-truth rules as a non-empty string). If in doubt you can always say

disabled="${(someExpression) as boolean}"