为什么NgModelController。$ modelValue!= $解析(attrs.ngModel)(范围)? [英] Why NgModelController.$modelValue != $parse(attrs.ngModel)(scope)?
问题描述
code: http://plnkr.co/edit/xPZM5E7tjYqlt5NIabIu? p = preVIEW 行号:17
在此code,如果我使用 CTRL $ modelValue = NVAL;
而不是 $解析(attrs.ngModel).assign(范围,NVAL);
则不起作用。能否请您点出了原因?
angModule.directive('moChangeProxy',函数($解析){
返回{
要求:'^ ngModel',
限制:'A',
链接:功能(范围,榆树,ATTRS,CTRL){
VAR proxyExp = attrs.moChangeProxy;
范围。$腕表(proxyExp,功能(NVAL){
如果(NVAL!= Ctrl键。$ modelValue){
//ctrl.$modelValue = NVAL; //这不起作用
$解析(attrs.ngModel).assign(范围,NVAL); //这个效果很好
}
});
elm.bind('模糊',函数(){
VAR proxyVal = $范围的eval(proxyExp)。
如果(按Ctrl。$ modelValue!= proxyVal){
范围。$应用(函数(){
$解析(proxyExp).assign(范围,CTRL $ modelValue);
});
}
});
}
};
});
我想通过不工作你的意思是,当变化发生时,它并不像所有$格式化运行的东西,并更新$ viewValue?
如果是这样,这是因为ngModelController钟表模式前pression的变革,而不是看自己的$ modelValue。
请参阅这些行:<一href=\"https://github.com/angular/angular.js/blob/master/src/ng/directive/input.js#L1046-L1065\">https://github.com/angular/angular.js/blob/master/src/ng/directive/input.js#L1046-L1065
如果您更新模型,则手表被触发,所有的机器被付诸行动。如果$ modelValue的ngModelController不知道这种变化。
Code: http://plnkr.co/edit/xPZM5E7tjYqlt5NIabIu?p=preview line-no:17
In this code if I use ctrl.$modelValue = nVal;
instead of $parse(attrs.ngModel).assign(scope, nVal);
then it does not work. Can you please point-out the reason?
angModule.directive('moChangeProxy', function ($parse) {
return {
require:'^ngModel',
restrict:'A',
link:function (scope, elm, attrs, ctrl) {
var proxyExp = attrs.moChangeProxy;
scope.$watch(proxyExp, function (nVal) {
if (nVal != ctrl.$modelValue) {
//ctrl.$modelValue = nVal; // This does not work
$parse(attrs.ngModel).assign(scope, nVal); // This works well
}
});
elm.bind('blur', function () {
var proxyVal = scope.$eval(proxyExp);
if(ctrl.$modelValue != proxyVal) {
scope.$apply(function(){
$parse(proxyExp).assign(scope, ctrl.$modelValue);
});
}
});
}
};
});
I guess that by "does not work" you mean that when the change occurs, it does not run stuff like all the $formatters and update the $viewValue?
If so, this is because ngModelController watches the "model expression" for changes rather than watching its own $modelValue.
See these lines: https://github.com/angular/angular.js/blob/master/src/ng/directive/input.js#L1046-L1065
If you update the model then the watch is triggered and all the machinery gets put into action. If you $modelValue, the ngModelController is not aware of the change.
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