问题
I have an array of Person objects
var persons = [
{Name:\'John\',Eligible:true},
{Name:\'Mark\',Eligible:true},
{Name:\'Sam\',Eligible:false},
{Name:\'Edward\',Eligible:false},
{Name:\'Michael\',Eligible:true}
];
and i am using select with ng-options like this:
<select ng-model=\"Blah\" ng-options=\"person.Name for person in persons\"></select>
I want to show the record with Eligible:false in red color.
So the problem is how do i use the ng-class in select inorder to achieve this? Since we are not using any option tag it wont work if i simply add ng-class in the select element itself.
回答1:
You could create a directive that processed the options after the ngOptions directive is processed that updated them with the appropriate classes.
Update: The old code had a few bugs, and I've learned a bit since I answered this question. Here is a Plunk that was redone in 1.2.2 (but should work in 1.0.X as well)
Here is updated the Code:
app.directive('optionsClass', function ($parse) {
return {
require: 'select',
link: function(scope, elem, attrs, ngSelect) {
// get the source for the items array that populates the select.
var optionsSourceStr = attrs.ngOptions.split(' ').pop(),
// use $parse to get a function from the options-class attribute
// that you can use to evaluate later.
getOptionsClass = $parse(attrs.optionsClass);
scope.$watch(optionsSourceStr, function(items) {
// when the options source changes loop through its items.
angular.forEach(items, function(item, index) {
// evaluate against the item to get a mapping object for
// for your classes.
var classes = getOptionsClass(item),
// also get the option you're going to need. This can be found
// by looking for the option with the appropriate index in the
// value attribute.
option = elem.find('option[value=' + index + ']');
// now loop through the key/value pairs in the mapping object
// and apply the classes that evaluated to be truthy.
angular.forEach(classes, function(add, className) {
if(add) {
angular.element(option).addClass(className);
}
});
});
});
}
};
});
Here's how you'd use it in your markup:
<select ng-model="foo" ng-options="x.name for x in items"
options-class="{ 'is-eligible' : eligible, 'not-eligible': !eligible }"></select>
It works like ng-class does, with the exception that it's on a per-item-in-the-collection basis.
回答2:
In this scenario you can only apply ng-class only if you use ng-repeat with option tags:
<select ng-model="Blah">
<option ng-repeat="person in persons" ng-class="{red: person.Eligible}">{{person.Name}}</option>
</select>
This will give custom class to your 'Eligible' persons, but CSS won't work consistently across bowsers.
Plunker.
回答3:
I wanted to comment on the accepted answer, but because I don't have enough reputation points, I must add an answer. I know that this is an old question, but comments where recently added to the accepted answer.
For angularjs 1.4.x the proposed directive must be adapted to get it working again. Because of the breaking change in ngOptions, the value of the option isn't anymore the index, so the line
option = elem.find('option[value=' + index + ']');
won't work anymore.
If you change the code in the plunker to
<select ng-model="foo" ng-options="x.id as x.name for x in items"
options-class="{ 'is-eligible' : eligible, 'not-eligible': !eligible }"></select>
As result the value of the option tag will now be
value="number:x" (x is the id of the item object)
Change the directive to
option = elem.find('option[value=\'number:' + item.id + '\']');
to get it working again.
Of course this isn't a generic solution, because what if you have not an id in your object?
Then you will find value="object:y" in your option tag where y is a number generated by angularjs, but with this y you can't map to your items.
Hopes this helps some people to get their code again working after the update of angularjs to 1.4.x
I tried also to use the track byin ng-options, but didn't get it to work.
Maybe people with more experience in angularjs then me (= my first project in angularjs)?
回答4:
The directive is one way, but I used a custom filter. If you know how to select your element, you should be fine here. The challenge was to find the current option element inside the select. I could have used the "contains" selector but the text in the options may not be unique for items. To find the option by value, I injected the scope and the item itself.
<select ng-model="foo" ng-options="item.name|addClass:{eligible:item.eligible,className:'eligible',scope:this,item:item} for item in items"></select>
and in the js:
var app = angular.module('test', []);
app.filter('addClass', function() {
return function(text, opt) {
var i;
$.each(opt.scope.items,function(index,item) {
if (item.id === opt.item.id) {
i = index;
return false;
}
});
var elem = angular.element("select > option[value='" + i + "']");
var classTail = opt.className;
if (opt.eligible) {
elem.addClass('is-' + classTail);
elem.removeClass('not-' + classTail);
} else {
elem.addClass('not-' + classTail);
elem.removeClass('is-' + classTail);
}
return text;
}
})
app.controller('MainCtrl', function($scope) {
$scope.items = [
{ name: 'foo',id: 'x1',eligible: true},
{ name: 'bar',id: 'x2',eligible: false},
{ name: 'test',id: 'x3',eligible: true}
];
});
Here you can see it work.
回答5:
The accepted answer did not work for me, so I found an alternative without a custom directive using track by :
<select ng-model="foo" ng-options="x.name for x in items track by x.eligible"></select>
Each option now gets the value x.eligible. In CSS you can style options with value = true (I think true has to be a string). CSS:
option[value="true"]{
color: red;
}
回答6:
In case you not only want to show them in red color but prevent the user from selecting the options, you can use disable when:
<select
ng-model="Blah"
ng-options="person.Name disable when !person.Eligible for person in persons">
</select>
You can then use CSS to set the color of disabled options.
回答7:
I can't write this as a comment, due to reputation, but I have updated the plunker for the accepted answer to work with Angular 1.4.8. Thanks to Ben Lesh for the original answer, it helped me a lot. The difference seems to be that newer Angular generates options like this:
<option class="is-eligible" label="foo" value="object:1">foo</option>
so the code
option = elem.find('option[value=' + index + ']');
wouldn't be able to find the option. My change parses ngOptions and determines what field of item was used for the label, and finds the option based on that instead of value. See:
http://plnkr.co/edit/MMZfuNZyouaNGulfJn41
回答8:
I know I am a bit late to the party, but for people who want to solve this with pure CSS, without using a directive you can make a css class like this:
select.blueSelect option[value="false"]{
color:#01aac7;
}
This css rule says : Find all elements with value = false with tag name 'option' inside every 'select' that has a class "blueSelect" and make the text color #01aac7; (a shade of blue)
In your case your HTML will look like this:
<select class="form-control blueSelect" name="persons" id="persons1"
ng-options="person as person.name for person in $ctrl.persons track by person.Eligible"
ng-model="$ctrl.selectedPerson" required>
<option disabled selected value="">Default value</option>
</select>
The track by inside the ng-options is what will hold what to track the options by, or the "value" field of each option. Notice that depending on your project needs , you might have to do some tweaking to make this work as per your requirements.
But that's not going to work right when there's multiple options with the same value for the Eligible field. So to make this work, we create a compound expression to track by, that way we can have unique values to track by in each option. In this case we combine both fields Name and Eligible
So now our html will look like this
<select class="form-control blueSelect" name="persons" id="persons2"
ng-options="person as person.name for person in $ctrl.persons track by (person.name + person.Eligible)"
ng-model="$ctrl.selectedPerson" required>
<option disabled selected value="">Default value</option>
</select>
and our css :
select.blueSelect option[value*="False"]{
color:#01aac7;
}
Notice the * next to value, this is a regular expression which means to find the word "False" somewhere in the value field of the option element.
Quick Edit You can also choose to disable the options with Eligible = False using the "disable when" in the ng-options expression , for example:
label disable when disable for value in array track by trackexpr
I'll leave how to use that in your case for you to find out ;-)
This works for simple css modifications, for more complex stuff you might need a directive or other methods. Tested in chrome.
I hope this helps someone out there. :-)
回答9:
I've found another workaround that was easier than adding a directive or filter, which is to add a handler for the onfocus event that applies the style.
angular.element('select.styled').focus( function() {
angular.element(this).find('option').addClass('myStyle');
});
来源：https://stackoverflow.com/questions/15264051/how-to-use-ng-class-in-select-with-ng-options