Angular2构建简单表单时没有ControlContainer的提供者

Question

这是我的表格:

app.component.html

<form [ngFormModel]="myForm">
    <my-child-component></my-child-component>
</form>    

app.component.ts

constructor ( private _formBuilder : FormBuilder ) {
    this.myForm = _formBuilder.group( {
        firstName : ["",Validators.required]
    } );
}

我的孩子组分:

 <input type="text" ngControl="firstName">  

错误:

   No provider for ControlContainer 
   [ERROR ->]<md-input
            ngControl="firstName"
            placeholder="First name">

如果我在app组件本身内移动输入,它会工作,但我的输入是在子组件内.

FORM_DIRECTIVES而FORM_PROVIDERS在顶部的应用程序级别被注入.我按照他们的向导完成了一切.

我也试过添加FORM_DIRECTIVES到孩子或app.component没有成功.

Answer 1

您可以使用ngFormControl指令而不是ngControl将控制变量传递给子,Input如下所示:

<form [ngFormModel]="myForm">
  <my-child-component [control]="myForm.controls.firstName"></my-child-component>
</form>

Child.component

@Component({
  selector: 'my-child-component',
  template: `
    <input type="text" [ngFormControl]="control">  
  `,
  directives: [FORM_DIRECTIVES]
})
export class Child {
  @Input() control: Control;
}

另见plunkr https://plnkr.co/edit/ydRAOmFG6FU6lxTonWzj?p=preview

NgControl指令是Child模板中必需的表单标记

也可以看看

• https://angular.io/docs/ts/latest/cookbook/dependency-injection.html#!#qualify-dependency-lookup-with-optional-and-host-

• https://github.com/angular/angular/blob/master/modules/%40angular/common/src/forms/directives/ng_control_name.ts#L106