使用angular2显示引导程序警报

Question

I want to display Bootstrap alert when the user has saved the data.

my code is as below:

html page:

<div class="alert alert-success" *ngIf="saveSuccess">
    <strong>Success!</strong>
</div>
<form #f="ngForm" (submit)="saveUser(f.value)">
        /////Some form fields
    <button class="form-control btn btn-primary" type="submit">save</button>
</form>

app.component.ts:

export class UserProfileComponent{
 saveSuccess: boolean;
 user: IUser;

saveUser(user:IUser) {
    this.headers = new Headers();
    this.headers.append('Content-Type', 'application/json');
    this.editUserForm = user;
    this._http.post('api/user/'+this._current_user._id, JSON.stringify(this.editUserForm),{
        headers: this.headers
    }).subscribe(function(data) {

        // if the update is successful then set the value to true
        // this is getting updated
        if (data){
            this.saveSuccess = true;
        }
        else{
            this.saveSuccess = false;
        }
    });
}

}

I want to display the alert when a successful POST is done.

I think i am missing how to bind the 'saveSuccess' variable to html so that alert can be displayed when the successful save is done. (I am new to Angular2)

Answer 1

Last night I didn't see it, it was probably too late. But your problem is not having the this context in the inline function where you set saveSuccess .

I'd suggest you use lambdas or "fat arrow function". Instead of

function(data) { ... }

you do

(data) => { ... }

This way the this context will be preserved. Just use it wherever you need inline function and you will have no problems anymore! :)

---

Your code with the lambda function:

export class UserProfileComponent{
    saveSuccess: boolean;
    user: IUser;

    saveUser(user:IUser) {
        this.headers = new Headers();
        this.headers.append('Content-Type', 'application/json');
        this.editUserForm = user;
        this._http.post('api/user/'+this._current_user._id, JSON.stringify(this.editUserForm),{
            headers: this.headers
        })
        .map((data: Response) => data.json) // <-- also add this to convert the json to an object
        .subscribe((data) => { // <-- here use the lambda

            // if the update is successful then set the value to true
            // this is getting updated
            if (data){
                this.saveSuccess = true;
            }
            else{
                this.saveSuccess = false;
            }
        });
    }
}

Answer 2

Consider this dynamic alert component:

Angular2 Service which create, show and manage it's inner Component? How to implement js alert()?

for example: .

this.alertCtmService.alertOK("Save changes???").subscribe(function (resp) {
    console.log("alertCtmService.alertOK.subscribe: resp=" + resp.ok);
    this.saveData();
}.bind(this) );

See this Demo here