形式 – 带有Observables的Angular 2 Formbuilder作为默认值

我对Angular 2 Form(formbuilder)的默认值有问题：
我的默认值是observables(我正在从服务器检索),所以我不能像这样实现它们：

export class UserComponent implements OnInit{

userForm: ControlGroup;
userData: any; // Initialise the observable var

ngOnInit():any {

    this.userData = this._dataService.getAllData() // My Observable
        .subscribe(
            data => {
                this.userData = data;
            }
        );

    this.userForm = this._formBuilder.group({
                  // below the default value
        'username': [this.userData.username,Validators.compose([ 
            this.usernameValid
        ])]
}

有人知道我需要改变什么吗？因为表单在输入字段中没有显示任何内容……

我会尝试这个,因为数据是异步加载的.因此,您需要在响应/接收时更新表单元素的值.

ngOnInit():any {
  this.userData = this._dataService.getAllData()
    .subscribe(
      data => {
        this.userData = data;
        this.userForm.controls.username.updateValue(
                this.userData.username);
      }
    );

  this.userForm = this._formBuilder.group({
    'username': [this.userData.username,Validators.compose([ 
        this.usernameValid
    ])];
}

原文地址：https://www.jb51.cc/angularjs/141241.html