我有自定义验证的指令(验证用户名尚不存在).验证使用$http服务询问服务器是否存在用户名,因此返回是一个promise对象.这对验证非常有用.表单无效并包含myform.$error.usernameVerify已经使用用户名.但是,user.username始终未定义,因此它违反了我的ng-model指令.我想这可能是因为.success中的函数正在创建它自己的作用域,并且控制器$scope上没有使用返回值.我如何解决这个问题,以便ng-model绑定仍然有效？
commonModule.directive("usernameVerify",[
'userSvc',function(userSvc) {
return {
require: 'ngModel',scope: false,link: function(scope,element,attrs,ctrl) {
ctrl.$parsers.unshift(checkForAvailability);
ctrl.$formatters.unshift(checkForAvailability);
function checkForAvailability(value) {
if (value.length < 5) {
return value;
}
// the userSvc.userExists function is just a call to a rest api using $http
userSvc.userExists(value)
.success(function(alreadyUsed) {
var valid = alreadyUsed === 'false';
if (valid) {
ctrl.$setValidity('usernameVerify',true);
return value;
}
ctrl.$setValidity('usernameVerify',false);
return undefined;
});
}
}
}
}
]);
这是我的模板：
<div class="form-group" ng-class="{'has-error': accountForm.username.$dirty && accountForm.username.$invalid}">
<label class=" col-md-3 control-label">Username:</label>
<div class="col-md-9">
<input name="username"
type="text"
class="form-control"
ng-model="user.username"
ng-disabled="user.id"
ng-minlength=5
username-verify
required />
<span class="field-validation-error" ng-show="accountForm.username.$dirty && accountForm.username.$error.required">Username is required.</span>
<span class="field-validation-error" ng-show="accountForm.username.$dirty && accountForm.username.$error.minlength">Username must be at least 5 characters.</span>
<span class="field-validation-error" ng-show="accountForm.username.$dirty && accountForm.username.$error.usernameVerify">Username already taken.</span>
</div>
</div>
@H_301_7@
@H_301_7@
对于这种情况,Angular有一个专门的$asyncValidators数组：
见https://docs.angularjs.org/api/ng/type/ngModel.NgModelController
ngModel.$asyncValidators.uniqueUsername = function(modelValue,viewValue) {
var value = modelValue || viewValue;
// Lookup user by username
return $http.get({url:'/api/users/' + value}).
then(function resolved() {
//username exists,this means validation fails
return $q.reject('exists');
},function rejected() {
//username does not exist,therefore this validation passes
return true;
});
};
@H_301_7@ 原文链接：https://www.f2er.com/angularjs/143751.html