预选选项表格ng-options list
[英]Pre-select option form ng-options list
问题描述
I'm trying to preselect a item in the list which is generated by ng-options directive. 
我试图在ng-options指令生成的列表中预先选择一个项目。 Could someone please tell me whats happening in the plunker? 有人可以告诉我the子发生了什么吗？
http://plnkr.co/edit/GTnR76HEnB5NxQRe484m?p=preview http://plnkr.co/edit/GTnR76HEnB5NxQRe484m?p=preview
<head>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.0.6/angular.min.js"></script>
<script>
function MyCntrl($scope) {
$scope.prop = {
"type": "select",
"name": "Service",
"values": [{
'name': "Service 1"
}, {
'name': "Service 2"
}, {
'name': "Service 3"
}, {
'name': "Service 4"
}]
};
$scope.selected1 = $scope.prop.values[1]
$scope.selected2 = {
"name": "Service 2"
}
}
</script>
</head>
<body>
<div ng-controller="MyCntrl">
Works <br>
<select ng-model="selected1" ng-options="v.name for v in prop.values">
</select> {{selected1}} <br>
Does not work. Why? <br>
<select ng-model="selected2" ng-options="v.name for v in prop.values">
</select>
{{selected2}}
</div>
</body>
</html>
2 个解决方案
解决方案1
7 已采纳 2015-03-10 07:16:31
Bijay Rai's statement is correct but not full answer. Bijay Rai的说法是正确的，但不是完整答案。
ngOption has rather complicated expressions and you should bother to examine documentation . ngOption表达式相当复杂，您应该检查文档 。 If you change the way the option's object is being tracked you can avoid using same object by reference as stated. 如果更改了跟踪选项对象的方式，则可以避免通过引用使用same object 。 For example, use select as pattern 例如，使用select as模式
<select ng-model="selected2" ng-options="v.id as v.name for v in prop.values">
</select>
Then you can simply assign selected like this: 然后，您可以像这样简单地分配所选内容：
$scope.selected2 = 3;
解决方案2
1 2015-03-10 07:01:24
$scope.prop = {
"type": "select",
"name": "Service",
"values": [{
'name': "Service 1"
}, {
'name': "Service 2"
}, {
'name': "Service 3"
}, {
'name': "Service 4"
}]
};
ng-options getting data from prop.values .... so selected1 is working cause it is predefined as $scope.prop.values[1] ng-options从prop.values中获取数据..所以selected1起作用了，因为它已预定义为$ scope.prop.values [1]
whereas selected2 is not referring to data inside prop.values ..... 而selected2并不引用prop.values内部的数据..
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