指令模板元素的唯一ID [英] Directive Template Unique IDs for Elements
问题描述
我有可以在页面上多次使用一个指令。在这个指令的模板,我需要使用的ID为输入元素这样我就可以绑定标签以它像这样:
<输入类型=复选框ID =ITEM1/><标签=ITEM1>开放< /标签>
现在的问题是,一旦我的指令,包含多次,ID为ITEM1已不再独特和标签不能正常工作(应该/不选中复选框,单击时)。
这是如何的问题解决吗?是否有分配为模板的命名空间或preFIX(如asp.net与ctl00 ...- preFIX一样)的方式?还是我,包括在每个ID属性其中包括从范围+静态ID指令-ID的角度-Ex的pression。是这样的:
<输入类型=复选框ID ={{directiveID}} +'ITEM1'/><标签={{directiveID}} +'ITEM1 '>开放< /标签>
编辑:
我的指令
module.directive('myDirective',函数(){
返回{
限制:'E',
适用范围:真,
templateUrl:'谐音/ _myDirective.html',
控制器:['$范围,$元素,$ ATTRS',函数($范围,$元,$ ATTRS){
...
} //控制器
};
}]);
我的HTML
< DIV CLASS =myDirective>
<输入类型=复选框ID =ITEM1/><标签=ITEM1>开放< /标签>
< / DIV>
更新
角1.3引入了原生懒一次性绑定。从角前pression文档:
一次性结合
这与::开头的前pression被认为是一个
一次性EX pression。一次性EX pressions将停止重新计算一次
它们是稳定的,这之后的第一个摘要,如果发生
前pression结果是一个非未定义的值(见值稳定
下面算法)。
块引用>本机的解决方案
.directive('myDirective',函数(){ VAR UNIQUEID = 1;
返回{
限制:'E',
适用范围:真,
模板:'<输入类型=复选框ID ={{:: UNIQUEID}}/>' +
'<标签={{:: UNIQUEID}}>开放< /标签>,
链接:功能(范围,ELEM,ATTRS){
scope.uniqueId ='项目'+ UNIQUEID ++;
}
}
})只能绑定一次:
- 如果您只需要绑定一个值,一旦你不应该使用绑定({{}} / NG绑定)
- ,因为它们使用$表绑定是昂贵的。在你的榜样,在每$消化,棱角分明的脏检查您的ID更改,但你只能设置一次即可。
- 检查该模块: https://github.com/Pasvaz/bindonce
解决方案:
.directive('myDirective',函数(){ VAR UNIQUEID = 1;
返回{
限制:'E',
适用范围:真,
模板:'<输入类型=复选框/><标签>&开放LT; /标签>,
链接:功能(范围,ELEM,ATTRS){
VAR项目='项目'+ UNIQUEID ++;
elem.find('输入')ATTR('身份证',项目)。
。elem.find(标签)ATTR('为',项目);
}
}
})I have a directive that can be used multiple times on a page. In the template of this directive, I need to use IDs for an input-Element so I can "bind" a Label to it like so:
<input type="checkbox" id="item1" /><label for="item1">open</label>
Now the problem is, as soon as my directive is included multiple times, the ID "item1" is not unique anymore and the label doesn't work correctly (it should check/uncheck the checkbox when clicked).
How is this problem fixed? Is there a way to assign a "namespace" or "prefix" for the template (like asp.net does with the ctl00...-Prefix)? Or do I have to include an angular-Expression in each id-Attribute which consists of the directive-ID from the Scope + a static ID. Something like:
<input type="checkbox" id="{{directiveID}} + 'item1'" /><label for="{{directiveID}} + 'item1'">open</label>
Edit:
My Directive
module.directive('myDirective', function () { return { restrict: 'E', scope: true, templateUrl: 'partials/_myDirective.html', controller: ['$scope', '$element', '$attrs', function ($scope, $element, $attrs) { ... } //controller }; }]);
My HTML
<div class="myDirective"> <input type="checkbox" id="item1" /><label for="item1">open</label> </div>
解决方案UPDATE
Angular 1.3 introduced a native lazy one-time binding. from the angular expression documentation:
One-time binding
An expression that starts with :: is considered a one-time expression. One-time expressions will stop recalculating once they are stable, which happens after the first digest if the expression result is a non-undefined value (see value stabilization algorithm below).
Native Solution:
.directive('myDirective', function() { var uniqueId = 1; return { restrict: 'E', scope: true, template: '<input type="checkbox" id="{{::uniqueId}}"/>' + '<label for="{{::uniqueId}}">open</label>', link: function(scope, elem, attrs) { scope.uniqueId = 'item' + uniqueId++; } } })
Only bind once:
- If you only need to bind a value once you should not use bindings ({{}} / ng-bind)
- bindings are expensive because they use $watch. In your example, upon every $digest, angular dirty checks your IDs for changes but you only set them once.
- Check this module: https://github.com/Pasvaz/bindonce
Solution:
.directive('myDirective', function() { var uniqueId = 1; return { restrict: 'E', scope: true, template: '<input type="checkbox"/><label>open</label>', link: function(scope, elem, attrs) { var item = 'item' + uniqueId++; elem.find('input').attr('id' , item); elem.find('label').attr('for', item); } } })
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