绑定多个复选框以在Grails中列出 [英] Binding multiple checkboxes to list in Grails
问题描述
看似简单，但显然很难.将一系列(有限的已知长度)复选框绑定到grails命令对象上的布尔值列表.当然，应该可以填充"命令对象以使用先前选择的值来还原视图.
It seems simple but is apparently very hard. Bind a (finite and known length) series of checkboxes to a list of booleans on a grails command object. It should of course be possible to "populate" the command object to restore the view, with the previous selected values.
例如，我有一个grails网络流.首先将4个复选框绑定到布尔列表中的一个条目.它切换到下一个状态并打印值-例如[true，true].向后浏览，所有复选框均为空(这很有意义-4个复选框和只有两个值).所以它应该是例如[false，true，false，true].
E.g I have a grails webflow. It start out by binding 4 checkboxes to an entry in a boolean list. It switches to next state and prints the values - e.g. [true,true]. Navigate back, and all the checkboxes are empty (which makes perfectly sense - 4 checkboxes and only two values). So it should rather be e.g. [false, true, false, true].
无论我做什么，我似乎都无法做到这一点.在春季，这很容易，只需将复选框绑定到value [0] .. [3] ...为什么在Grails中这么简单的东西就这么难?！
No matter what I do, I cant seem to make this happen. In spring it would be easy, simply bind the checkbox to value[0]..[3]... Why is somehthing this simple so hard in Grails?!
请帮助，这真的会让我高兴！
Please help, it would really make my day!
示例命令对象:
class TestCmdObj {
List<Boolean> boolListOne = []
}
控制器中的绑定方法示例(在流程动作中执行闭包):
Example binding method in controller (closure executed in flow action):
private def doBindAndValidateBoolList = {
bindData(flow.testCmdObj, params, [include:['boolListOne']])
}
到目前为止，一切都很好.当显示流中的下一页时，此方法实际上起作用，testCmdObj.boolListOne对于选中的复选框显示为true..
So far so good. This actually works when displaying next page in flow, the testCmdObj.boolListOne displays true for the checkboxes checked..
GSP代码很简单，并使用:
The GSP code is simple, and uses:
<g:checkBox name="boolListOne"/>
<g:checkBox name="boolListOne"/>
<g:checkBox name="boolListOne"/>
<g:checkBox name="boolListOne"/>
在下一个视图中，我可以打印出$ {testCmdObj.boolListOne}，并打印出与我检查的一样多的"true"值.(例如[true，true])如果我向后浏览，则该复选框是空的...我又能理解，因为它们都具有相同的名称...
In the next view, I can print out ${testCmdObj.boolListOne} and it prints out as many "true" values, as I checked of..(e.g. [true, true]) If I navigate back, the checkboxes are emtpy... Which, again, I can understand, since they all have the same name...
推荐答案
希望最终确定上述建议/评论之间的所有内容.
Wanted to finalise all in between the above suggestions / comments.
- 如果您声明复选框的迭代并调用它们
<g:each in="someIteration" var="a">
<g:checkBox name="something" value="${a.someCondition}"
checked="${a.someCondition}" />
</g:each>
您的控制者将以
String[L]
有点像String[] something的验证对象
尽管您仍将其声明为List something=[].
Your controller in grails will pick up this up as
String[L]
A bit like a validation object of String[] something
Although you would still declare this as List something=[].
只要最终用户选择了多个复选框，此方法也将起作用.并且您的验证对象将在此时List something=[]
This also appears to work so long as the end user has selected more than 1 checkbox. and your validation object would pickup at this point List something=[]
上面的问题是，如果选择1，则参数以string而不是list
The issue with above is that if 1 selection is made the param is received more as a string than a list
如果您不依赖于对象的自动绑定，那么上面的操作没什么问题，
Nothing wrong with above if you are not relying on auto binding of objects since you would do
List myList = params.list('something')
这时，grails会将1或倍数转换为列表.但这不会将单个复选框绑定到验证列表元素.
at this point grails will convert whether 1 or multiple into the list. But this won't bind a single checkbox to a validation list element.
要从验证的角度解决此问题，就是将其声明为List something=[]
To fix this from a validation point of view would be to declare it as List something=[]
<g:each in="someIteration" status="i" var="a">
<g:checkBox name="something[${i}]" value="${a.someCondition}"
checked="${a.someCondition}" />
</g:each>
现在，无论选择1个复选框还是多个复选框，它都将在something列表下(如['null','whatever','null','null'])被拾取.
Now this will be picked up under something list like ['null','whatever','null','null'] regardless of 1 selection or multiple check box selection.
使用status字段并将名称从something重命名为something[${i}]
It is to use the status field and rename name from something to something[${i}]
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