I have read about it in other posts, but I couldn't figure it out.
I have an array,
$scope.items = [ {ID: '000001', Title: 'Chicago'}, {ID: '000002', Title: 'New York'}, {ID: '000003', Title: 'Washington'}, ];
I want to render it as:
<select> <option value="000001">Chicago</option> <option value="000002">New York</option> <option value="000003">Washington</option> </select>
And also I want to select the option with ID=000002.
I have read select and tried, but I can't figure it out.
The ng-options directive fills a <select> element with <options>. The ng-options directive uses an array to fill the dropdown list. In many cases it would be easier to use the ng-repeat directive, but you have more flexibility when using the ng-options directive.
Definition and Usage. The ng-selected directive sets the selected attribute of an <option> element in a <select> list. The option will be selected if the expression inside the ng-selected attribute returns true. The ng-selected directive is necessary to be able to shift the value between true and false .
In AngularJS when you are using ng-options, you can filter out the options by calling a custom function you have in the controller. Let's say you have following set of employees and when you display all these employees inside HTML select using ng-options, you can see all the employees in a dropdown.
In my opinion the correct way to set a default value is to simply pre-fill your ng-model property with the value selected from your ng-options , angular does the rest. Essentially when you define the $scope property your select will bind to assign it the default value from your data array.
One thing to note is that ngModel is required for ngOptions to work... note the ng-model="blah"
which is saying "set $scope.blah to the selected value".
Try this:
<select ng-model="blah" ng-options="item.ID as item.Title for item in items"></select>
Here's more from AngularJS's documentation (if you haven't seen it):
for array data sources:
- label for value in array
- select as label for value in array
- label group by group for value in array = select as label group by group for value in array
for object data sources:
- label for (key , value) in object
- select as label for (key , value) in object
- label group by group for (key, value) in object
- select as label group by group for (key, value) in object
For some clarification on option tag values in AngularJS:
When you use ng-options
, the values of option tags written out by ng-options will always be the index of the array item the option tag relates to. This is because AngularJS actually allows you to select entire objects with select controls, and not just primitive types. For example:
app.controller('MainCtrl', function($scope) { $scope.items = [ { id: 1, name: 'foo' }, { id: 2, name: 'bar' }, { id: 3, name: 'blah' } ]; });
<div ng-controller="MainCtrl"> <select ng-model="selectedItem" ng-options="item as item.name for item in items"></select> <pre>{{selectedItem | json}}</pre> </div>
The above will allow you to select an entire object into $scope.selectedItem
directly. The point is, with AngularJS, you don't need to worry about what's in your option tag. Let AngularJS handle that; you should only care about what's in your model in your scope.
Here is a plunker demonstrating the behavior above, and showing the HTML written out
Dealing with the default option:
There are a few things I've failed to mention above relating to the default option.
Selecting the first option and removing the empty option:
You can do this by adding a simple ng-init
that sets the model (from ng-model
) to the first element in the items your repeating in ng-options
:
<select ng-init="foo = foo || items[0]" ng-model="foo" ng-options="item as item.name for item in items"></select>
Note: This could get a little crazy if foo
happens to be initialized properly to something "falsy". In that case, you'll want to handle the initialization of foo
in your controller, most likely.
Customizing the default option:
This is a little different; here all you need to do is add an option tag as a child of your select, with an empty value attribute, then customize its inner text:
<select ng-model="foo" ng-options="item as item.name for item in items"> <option value="">Nothing selected</option> </select>
Note: In this case the "empty" option will stay there even after you select a different option. This isn't the case for the default behavior of selects under AngularJS.
A customized default option that hides after a selection is made:
If you wanted your customized default option to go away after you select a value, you can add an ng-hide attribute to your default option:
<select ng-model="foo" ng-options="item as item.name for item in items"> <option value="" ng-if="foo">Select something to remove me.</option> </select>
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