AngularJS在ng-repeat中重新运行ng-if

Question

I'm trying to run an ng-if condition, which has a function attached, when function is run. The ng-if only runs on initial render, but I want to rerun the ng-if function after making a $http call.

Steps:

1. List is rendered
2. Ng-if runs functions to test for certain conditions
3. User clicks on a link
4. A http.post function is run
5. On success the ng-if should be run again on all items inside the ng-repeat.

The function attached to the ng-if compares two arrays and returns a boolean. The return values dictates what should be dispayed/rendered in the dom.

The array for the ng-repeat comes from a http.get call. I have been trying to run the http.get call function again, but this doesn't trigger a the ng-if. A page refresh does though.

Any suggestions?

Code:

Ng-repeat:

      <tr ng-repeat="y in courses | filter:{Category: x.Category} | filter:search | filter:location">
            <td>
                {{y.Title}}
            </td>
            <td >
                <div ng-bind-html="y.Description | sanitize"></div>
                <a style="font-weight: 700;" href="{{y.AttachmentFiles.results[0].ServerRelativeUrl}}" target="_blank">Read more</a>
            </td>
            <td>
                {{y.Date | date:"dd-MM-yyyy"}}
            </td>
            <td>
                {{y.Location}}
            </td>
            <td>
                <a href="" ng-click="enrollUser(y)" ng-if="!isEnrolled(y.Title)" style="font-weight: 700;" >
                    <i class="fa fa-arrow-circle-right"></i> 
                    Enroll
                </a>
                <span ng-if="isEnrolled(y.Title)">
                    <i class="fa fa-check-circle-o"></i> 
                    Already Enrolled
                </span>
            </td>
        </tr>

The ng-if in question:

               <a href="" ng-click="enrollUser(y)" ng-if="!isEnrolled(y.Title)" style="font-weight: 700;" >
                    <i class="fa fa-arrow-circle-right"></i> 
                    Enroll
                </a>
                <span ng-if="isEnrolled(y.Title)">
                    <i class="fa fa-check-circle-o"></i> 
                    Already Enrolled
                </span>

The function attached to the ng-if:

  $scope.isEnrolled = function(Title) {
                for (var i = 0; i < $scope.enrollments.length; i++) {
                    if ($scope.enrollments[i].Course === Title) {
                        console.log('Value exist');
                        return true;
                    }
                }
            }   

The enrollUser() function:

$scope.enrollUser = function(item) {
$scope.userEmail = user.get_email();
var endpointUrl = "https://xxx.xxx.com/academy/_api/lists/getbytitle('EmployeeEnrollments')/items";
    var itemPayload = {
    CourseID: item.ID,
    Category: item.Category,
    Course: item.Title,
    Status: "Pending",
    Employee: $scope.userEmail,
    __metadata: {
        type: 'SP.Data.EmployeeEnrollmentsListItem'
    }
};
$http({
       method: "POST",
       url : endpointUrl,
       data: itemPayload,  
       headers: {
                   "Content-Type" : "application/json;odata=verbose",
                   "Accept": "application/json;odata=verbose",
                   "X-RequestDigest": $("#__REQUESTDIGEST").val() 
                }          
}).success(function (data, status, headers, config) { 

    //On success display notification
    Notification.primary('You have been succesfully enrolled');

    //Reload courses
    $scope.reload();
})

}

The reload() function:

$scope.reload = function(){
//Get all courses
$http({
    method: "GET",
    url: "https://xxx.xxx.com/academy/_api/lists/getbytitle('CourseCatalogue')/items?$expand=AttachmentFiles",
    headers: {
        "Accept": "application/json;odata=verbose"
    }
}).success(function(data, status, headers, config) {
    //Save results on $scope.courses array
    $scope.courses = data.d.results;
    })
}

Answer 1

Angular will auto run the ng-if expression if the return value of expression is changed. In this case isEnrolled() , if the return value changes, Angular will auto update the DOM.

So, your AJAX call ( enrollUser method) should be updating the $scope.enrollments or the $scope.courses .

Answer 2

Because your ng-if calls a function. And the function is called only once. Which is when the element is rendered.

Solution: create a boolean variable and attach that to the ng-if , now whenever that variable changes value the ng-if would be reevaluated. Upon the success of your ajax call, go through each courses and attach a isEnrolled variable, then do the checking there. In your html, set the ng-if='y.isEnrolled'

in your reload function:

$scope.reload = function(){
//Get all courses
$http({
    method: "GET",
    url: "https://intra.monjasa.com/academy/_api/lists/getbytitle('CourseCatalogue')/items?$expand=AttachmentFiles",
    headers: {
        "Accept": "application/json;odata=verbose"
    }
}).success(function(data, status, headers, config) {
    //Save results on $scope.courses array
    $scope.courses = data.d.results;

    _.each($scope.courses, function(course,i){

       course.isEnrolled = //do your logic here;   

    });

    })
}

your html would then be:

    <tr ng-repeat="y in courses | filter:{Category: x.Category} | filter:search | filter:location">
        <td>
            {{y.Title}}
        </td>
        <td >
            <div ng-bind-html="y.Description | sanitize"></div>
            <a style="font-weight: 700;" href="{{y.AttachmentFiles.results[0].ServerRelativeUrl}}" target="_blank">Read more</a>
        </td>
        <td>
            {{y.Date | date:"dd-MM-yyyy"}}
        </td>
        <td>
            {{y.Location}}
        </td>
        <td>
            <a href="" ng-click="enrollUser(y)" ng-if="y.isEnrolled" style="font-weight: 700;" >
                <i class="fa fa-arrow-circle-right"></i> 
                Enroll
            </a>
            <span ng-if="y.isEnrolled">
                <i class="fa fa-check-circle-o"></i> 
                Already Enrolled
            </span>
        </td>
    </tr>