问题
I have the following setup:
App/Directive
var app = angular.module("MyApp", []);
app.directive("adminRosterItem", function () {
return {
restrict: "E",
scope: {
displayText: "@"
},
template: "<td>{{ displayText }}</td>", // should I have this?
link: function(scope, element, attrs){
// What do I put here? I don't seem to have any
// element to initialize (set up event handlers, for example)
},
compile: function(?,?,?){} // should I have this? If so, what goes inside?
}
});
Controller
function PositionsController($scope) {
$scope.positions = [{ Name: "Quarterback", Code: "QB" },
{ Name: "Wide Receiver", Code: "WR" }
];
}
HTML:
<div ng-app="MyApp">
<div ng-controller="PositionsController">
<table>
<tr ng-repeat="position in positions">
<admin-roster-item displayText="{{ position.Name + ' (' + position.Code + ')' }}"></admin-roster-item>
</tr>
</table>
</div>
</div>
It's a very simple example, but I can't get it to render. Perhaps there's something that tutorials aren't telling me, or that is secret Angular knowledge?
If I remove the directive inside the <tr ng-repeat="..." /> and place <td>{{ displayText }}</td> instead, it will show all records.
But I want the directive to be more complicated than just a single <td>{{}}</td> (eventually) so that I could reuse this directive in multiple apps.
So, I'm really asking how do we properly create a directive that goes inside ng-repeat? What am I missing? What should be taken off from the code above?
回答1:
Agree that you need to think about where the directive begins and ends. Here's a plnkr that illustrates a directive bound to each item in the array - http://plnkr.co/edit/IU8fANreYP7NYrs4swTW?p=preview
If you want the directive to encapsulate the enumerating of a collection defined by a parent scope it gets a bit tricker. I'm not sure if the following is 'best practice', but it's how i've handled it -- http://plnkr.co/edit/IU8fANreYP7NYrs4swTW?p=preview
When relying on the directive to perform the iteration you get involved with transclusion, which is a made up word that means (as i understand it) take the content defined in the parent, push it into the directive and then evaluate it. I've been working with angular for a few months, and I'm starting to think that asking the directive to iterate is a smell, and I've always been able to design around it.
回答2:
Ignoring all the theoretical aspects, you can get your code to work by making two simple changes.
- don't use mixed case in your attribute names.
displaytextnotdisplayText - put the
<td>tags outside the directive, in the template
Do that and it will work; it think those are both Angular bugs.
回答3:
i think the right way to approach this would be to send the object into admin roster item, like this:
<tr ng-repeat="position in positions">
<admin-roster-item pos="position">
</admin-roster-item>
</tr>
and in the directive:
var app = angular.module("MyApp", []);
app.directive("adminRosterItem", function () {
return {
restrict: "E",
scope: {
pos: "@"
},
template: "<td>{{ formattedText }}</td>", // should I have this?
link: function(scope, element, attrs){
// all of this can easily be done with a filter, but i understand you just want to
// know how it works
scope.formattedText = scope.pos.Name + ' (' + scope.pos.Code + ')';
}
}
});
PS. i didn't test this!
回答4:
Instead of writing your directive as a child of ng-repeat, try keeping the custom directive on the same level as ng-repeat, this
<tr ng-repeat="position in positions" admin-roster-item displayText="{{ position.Name + ' (' + position.Code + ')' }}"></tr>
And furthermore, allow your custom directive to be used as an attribute. AngulaJS has defined ng-repeats priority as 1000, so at times when you custom directive is made, it does not go down well with ng-repeat.
A second option (try only if the first one fails) is to set the priority of your custom directive more than that of ngRepeat i.e. to 1001.
回答5:
I had the similar issue, where the ng-repeat in my view wass not evaluated if the view contained directive ('mydirective')
My directive definition was
angular.module('myApp')
.directive('myDirective', function () {
return {
templateUrl: 'components/directives/mydirective.html',
restrict: 'EA',
controller: 'MyDirectiveController',
controllerAs: 'vm',
link: function (scope, element, attrs) {
}
};
});
and my view controller definition was
angular.module('myApp')
.component('myView', {
templateUrl: 'app/views/myview.html',
controller: myViewComponent,
controllerAs: "vm"
});
you can notice both controllers are refered by 'vm' by using 'controllerAs' parameter. This is the reason for the problem. When the directive is present in the view, angular always refers the 'vm' defined in directive controller rather than view's.
When I give different names for controller references, problem disappeared
Now, My directive definition is
angular.module('myApp')
.directive('myDirective', function () {
return {
templateUrl: 'components/directives/mydirective.html',
restrict: 'EA',
controller: 'MyDirectiveController',
controllerAs: 'directiveVM',
link: function (scope, element, attrs) {
}
};
});
and my view controller definition was
angular.module('myApp')
.component('myView', {
templateUrl: 'app/views/myview.html',
controller: myViewComponent,
controllerAs: "viewCtrlVM"
});
Hope it helps.
回答6:
Had exact same problem. Had a custom directive in an ng-repeat, table->tr->td->directive, and when sorting the table using ng-repeat and Array.sort the table did change order but the directives did not re-render. The problem was I was using
track by $index
removed the track by index from the ng-repeat and it was fixed.
来源：https://stackoverflow.com/questions/15754889/angular-directive-does-not-evaluate-inside-ng-repeat