未捕获的TypeError：无法设置只有getter的[object Object]的属性堆栈

这个错误并不完全清楚,所以我很难弄清楚发生了什么.我跟着一个angular university article.我想也许有一些重大的变化,所以我检查了angular2更改日志,但没有发现任何与我的问题有关的反应形式.

任何帮助将在这里受到赞赏.我将继续寻找解决方案.

addevent.component.ts

@Component({
  selector: 'addevent',templateUrl: 'addevent.component.html',styleUrls: ['addevent.scss']
})
export class AddEvent {

  // vars
  private _addEventForm:FormGroup;
  private _eventTitle:FormControl;
  private _eventDescription:FormControl;

  constructor(private _addEventService:AddEventService,private _formBuilder:FormBuilder) {
    // init vars
    this. _eventTitle = new FormControl('',Validators.required);
    this._eventDescription = new FormControl('',Validators.required);
    this._addEventForm = _formBuilder.group({
      'eventTitle': this._eventTitle,'eventDescription': this._eventDescription
    });
  }

  private addEvent():void {
    console.log(this._addEventForm);
    //this._addEventService.addEvent();
  }

}

addevent.component.html

<div class="h3 content-title">Add Event</div>

<form [formGroup]="_addEventForm" (ngSubmit)="addEvent()">
  <p>
    <label>Title</label>
    <input type="text" formControlName="eventTitle">
  </p>
  <p>
    <label>Description</label>
    <input type="text" formControlName="eventDescription">
  </p>
  <p>
    <button type="submit" [disabled]="_addEventForm.invalid">Submit</button>
  </p>
</form>

dashboard.module.ts

@NgModule({
  declarations: [Dashboard,Navbar,Sidebar,Home,Profile,Events,AddEvent],imports: [BrowserModule,FormsModule,ReactiveFormsModule,HttpModule],providers: [ContentSwap,SidebarActivity,AuthService,FirebaseAuthService]
})
export class DashboardModule {}